The present invention relates to a kit for the removal of colour from dyed materials, in particular for the removal of colour from dyed hair, especially human hair.

There are a number of existing compositions for removing colour from hair which has been dyed. However many of these are unsatisfactory. For example the compositions may cause damage to the hair; the chemicals used in some prior art compositions are hazardous to health; and in many cases the result achieved is incomplete or inconsistent. In some cases satisfactory colour removal may not be achieved because a colour removal composition is not correctly prepared or correctly applied to the hair.

It is an aim of the present invention to provide a colour removal kit which can be used to efficiently and safely remove colour from dyed hair with a high degree of reproducibility.

According to the first aspect of the present invention there is provided a colour removal kit comprising:

a) a composition comprising an activator species including a metal ion;

b) a composition comprising a sulfur containing species;

c) a carrier composition;

d) an acidic composition; and

e) a composition comprising an oxidising agent; wherein components (a), (b) and (c) are provided in unit dose form.

Component (a) comprises an activator species including a metal ion.

Suitable activator species include divalent and trivalent metal species, for example divalent and/or trivalent ions of zinc, magnesium, aluminium and calcium. Preferably the activator species includes zinc or especially magnesium ions. The divalent or trivalent ions may be provided in any suitable form. Preferably they are provided as salts, for example carbonates, sulfates, chlorides, acetates or formates. More preferably they are provided as organic acid salts, for example formate or acetate. Suitably the activator species may be selected from zinc acetate, magnesium acetate, zinc oxide, magnesium carbonate, zinc sulphate, aluminium acetate, calcium acetate and mixtures thereof. Zinc acetate and magnesium acetate are particularly preferred. Acetate or formate salts of divalent or trivalent metals may be used directly in the composition of component (a). Alternatively the corresponding acid and a different metal salt may be used, for example magnesium sulphate and acetic acid. Preferably the preformed salt is used. Component (a) is preferably provided as an aqueous composition. Other solvents or cosolvents may be present. However in preferred embodiments water is the only solvenr present in component (a).

Suitably the composition of component (a) comprises at least 1 w% of the activator species, preferably at least 5 wt%, more preferably at least 10 wt%, suitably at least 15 wt%, preferably at least 20 wt%, for example at least 25 wt% or at least 30 wt%. Preferably component (a) comprises up to 80 wt% of the activator species, suitably up to 70 wt%, more preferably up to 60 wt%, suitably up to 50 wt% for example up to 45 wt% or 40 wt%. Component (a) suitably consists essentially of water and an activator species comprising a metal ion.

Component (b) comprises a sulphur-containing species. Suitable sulfur-containing species include formamidine sulfinic acid, hydrosulfoxylate, hydrosulfite, dithionite, sulfoxylic acid and salts and derivatives thereof. One preferred sulfur- containing species is formamidine sulfinic acid which hydrolyses to form the nucleophilic species HS0 ₂ ^" (hydrosulfoxylate). Another suitable sulfur-containing species is sodium hydrosulfite (Na ₂ S ₂ 0 ₄ ) which, on dissolving in water, forms sodium bisulfite and sodium hydrosulfoxylate in equal molar proportions.

In some preferred embodiments the sulfur-containing nucleophile comprises a salt of sulfoxylic acid of formula HS0 ₂ ^{" +} M. M is preferably hydrogen, an alkali metal or a quaternary ammonium species. Such salts may suitably be generated from formamidine sulphinic acid, dithionite (S ₂ 0 ₄ ^2~ ) or the compounds sold by BASF under the trade marks Formosul (HOCH ₂ S0 ₂ ^" Na ⁺ ) and Decrolin ((HOCH ₂ S0 ₂ ^" ) ₂ Zn ²⁺ ). However the compounds sold under the trade marks Formosul and Decrolin produce formaldehyde during use. This makes them unsuitable for personal care applications as there are strict limits on levels of formaldehyde than can be used in such compositions.

In preferred embodiments the compositions of component (b) do not comprise compounds which form formaldehyde during use.

Preferably the composition of component (b) comprises formamidine sulphinic acid. Under mildly alkaline conditions it is believed that the formamidine sulfinate hydrolyses to release HS0 ₂ ^{" +} M which is believed to be an active colour removal species. It is also possible to use mixed formamidine / carbamoyl sulfinic acids to generate the reactive species. It is known from the prior art to use aminomethanesulfinic acid for colour removal. Under the conditions of use this compound was not very effective but for the avoidance of doubt, the compositions of component (b) of the kit of the present invention do not comprise aminomethanesulfinic acid. Component (b) preferably comprises at least 5 wt% of the sulfur-containing nucleophile, preferably at least 20 wt%, more preferably at least 50 wt%, preferably at least 75 wt%, preferably at least 90 wt%, suitably at least 95 wt%, for example at least 98 wt% or at least 99 wt%. In preferred embodiments component (b) comprises formamidine sulfinic acid. Suitably component (b) consists essentially of formamidine sulfinic acid.

Component (c) is a carrier composition. Component (c) is suitably mixed with component (a) and component (b) to provide a colour removal composition for application to the hair. Component (c) suitably has a consistency that enables it to be easily applied to the hair. Preferably component (c) is in the form of a gel or paste. Preferably it is an aqueous based gel or paste.

Preferably component (c) comprises a sulfur-containing species. Preferred sulfur-containing species are nucleophilic sulfur-containing species. Suitably the sulfur containing species is different to the sulfur containing species present in component (b). Preferably the sulfur- containing species is selected from thiocyanate, thioglycolic acid, thiocarbamate, carbamoylsulphinic acid, thioethanol and mixtures and/or salts thereof. In an especially preferred embodiment component (c) comprises thioglycolic acid.

The sulfur-containing species is suitably present in component (c) in an amount of from 0.01 to 20 wt%, preferably from 0.1 to 10 wt%, more preferably from 0.25 to 7.5 wt%, preferably from 0.5 to 5 wt%, suitably from 0.75 to 2.5 wt%, preferably from 0.8 to 2 wt%, for example from 0.9 to 1 .5 wt% or from 1 to 1 .25 wt%.

The carrier composition of component (c) suitably includes a swelling agent. Preferred swelling agents include urea, guanidine, formamide, thiodiglycol, ethylene glycol and propylene carbonate. One preferred swelling agent is urea. The swelling agent is preferably present in component (c) an amount of at least 0.1 wt%, suitably at least 1 wt%, more preferably at least 2.5 wt%, suitably at least 5 wt%, for example at least 7wt%, at least 8 wt% or at least 9 wt%. Component (c) preferably comprises up to 50wt% swelling agent, suitably up to 40wt%, more preferably up to 30wt%, suitably up to 20 wt%, for example up to 15wt%, up to 14 wt% or up to 13 wt%.

The composition of component (c) is preferably an aqueous composition. Suitably it comprises at least 40 wt% water, suitably at least 50 wt%, preferably at least 60 wt%, more preferably at least 70 wt%. It may comprise up to 95 wt% water, for example at least 90 wt%.

The composition of component (c) may further comprise one or more ingredients selected from surfactants, emulsifiers, colourants, fragrances, buffers, solvents, thickening agents and conditioning agents.

Preferably component (c) comprises a surfactant. Any suitable surfactant or mixture of surfactants may be included, for example anionic, cationic, amphoteric or nonionic surfactants. Suitably surfactants will be known to the person skilled in the art. Nonionic surfactants are especially preferred.

Suitable non-ionic surfactants will be known to the person skilled in the art and includes for example ethoxylated and polyethoxylated surfactants. One especially preferred non-ionic surfactant used herein is polysorbate 80.

Component (c) suitably comprises from 0.1 to 30 wt% non-ionic surfactants, preferably from 0.5 to 20 wt%, suitably from 1 to 20 wt%, preferablyfrom 2 to 25 wt%.

Component (c) may include a buffer. Suitable pH buffers include 2-amino-2-methyl-1 -propanol. Other suitable buffers will be known to the person skilled in the art.

Suitably the composition of component (c) has a pH of from 3 to 1 1 . Preferably the composition has a pH of from 7 to 10, for example from 9 to 10 but a lower pH is still practical. Component (c) may include a thickener. Suitable thickeners will be known to the peron skilled in the art. Preferred thickeners are non-ionic thickeners. One suitable thickener is hydroxyethylcellulose. Preferably the composition of component (c) comprises from 0.1 to 20 wt%, preferably from 0.5 to 10 wt%, more preferably from 0.75 to 5 wt% of thickeners, for example from 1 to 2.5 wt%. Components (a), (b) and (c) are provided in unit dose form. By this we mean that the kit of the present invention comprises an amount of each of components (a), (b) and (c) sufficient to achieve a single colour removal event, for example the removal of colour from a single head of dyed hair.

When the kit of the present invention is used, components (a), (b) and (c) are mixed together prior to contact with a dyed material to provide a colour removal composition. Suitably the kit of the present invention comprises components (a), (b) and (c) in relative amounts such that admixture thereof provides a colour removal composition having optimal properties.

Suitably the weight ratio of component (a) to component (b) included in the kit of the present invention is from 1 :1 to 5:1 , preferably from 2:1 to 4:1 , more preferably from 2.5:1 to 3:1 .

Suitably the weight ratio of component (a) to component (c) included in the kit of the present invention is from 1 :1 to 1 :20, preferably from 1 :3 to 1 :10, more preferably from 1 :5 to 1 :7. Suitably the weight ratio of component (b) to component (c) included in the kit of the present invention is from 1 :2 to 1 :50, preferably from 1 : 10 to 1 :20, more preferably from 1 : 15 to 1 :18.

Suitably upon admixture of components (a), (b) and (c), the kit of the present invention provides a colour removal composition comprising from 0.1 to 20 wt%, preferably from 0.5 to 15 wt%, more preferably from 1 to 10 wt% of an activator species including a metal ion.

Suitably upon admixture of components (a), (b) and (c), the kit of the present invention provides a colour removal composition comprising from 0.1 to 20 wt%, preferably from 0.5 to 15 wt%, more preferably from 1 to 10 wt% of a sulfur-containing species, preferably formamidine sulfinic acid.

Suitably upon admixture of components (a), (b) and (c), the kit of the present invention provides a colour removal composition comprising from 0.1 to 20 wt%, preferably from 0.5 to 15 wt%, more preferably from 1 to 10 wt% of a swelling agent, preferably urea.

Suitably upon admixture of components (a), (b) and (c), the kit of the present invention provides a colour removal composition comprising from 0.01 to 20 wt%, preferably from 0.1 to 10 wt%, more preferably from 0.5 to 2 wt% of a nucleophilic sulfur-containing species, for example thioglycolic acid. Suitably upon admixture of components (a), (b) and (c), the kit of the present invention provides a colour removal composition comprising from 3 to 7 wt% of an activator species including a metal ion and from 3 to 7 wt% of a sulfur-containing species.

Suitably upon admixture of components (a), (b) and (c), the kit of the present invention provides a colour removal composition comprising from 3 to 7 wt% magnesium acetate, from 3 to 7 wt% of formamidine sulfinic acid and from 3 to 7 wt% of urea.

The kit of the present invention preferably comprises from 1 to 100g component (a), preferably from 10 to 70g, more preferably from 20 to 50g, suitably from 30 to 40g.

The kit of the present invention preferably comprises from 1 to 50g component (b), preferably from 5 to 20g, more preferably from 8 to 20g, suitably from 10 to 15g.

The kit of the present invention preferably comprises from 1 to 1000g component (c), preferably from 50 to 500g, more preferably from 100 to 400g, suitably from 150 to 250g. Because components (a), (b) and (c) are provided in unit dose, admixture thereof provides a colour removal composition comprising the optimum concentration of active components. Providing the components of the composition in unit dose form ensures that the correct amount of each component is present in the admixed colour removal composition. Including too much or too little of a particular component could lead to poor performance, inconsistent results or damage to the hair. It might also provide a composition having an undesirable consistency that is difficult to handle.

The kit of the present invention further comprises component (d), an acidic composition. The acidic composition preferably has a pH of from 1 to 6.5, more preferably from 2 to 6, more preferably from 3 to 5, for example from 3 to 4 or from 3 to 3.5.

Suitable acids that may be included in the composition of component (d) include organic and inorganic acids. Suitable organic acids include ascorbic acid, acetic acid, oxalic acid, lactic acid, formic acid, citric acid, glycolic acid, glucuronic acid, malic acid, mandelic acid and tartaric acid.

Suitable inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphorous acid, hypophosphorous acid and phosphoric acid. The acidic composition of component (d) is preferably a reducing composition. Thus the composition preferably comprises a reducing agent. In some embodiments the reducing agent may be the same as the acid and the composition may comprise a reducing acid. Suitably the composition comprises a reducing acid selected from ascorbic acid, oxalic acid, lactic acid, formic acid, citric acid glycolic acid, glucuronic acid, malic acid, mandelic acid and tartaric acid.

The skilled person will appreciate that under the conditions of pH used the acid may be present in the form of a salt. In some embodiments the acid may be incorporated into the composition in the form of a salt for ease of preparation.

In especially preferred embodiments the component (d) comprises ascorbic acid.

In preferred embodiments component (d) comprises an organic reducing acid in an amount of from 0.1 to 25 wt%, preferably from 1 to 20 wt%, more preferably from 5 to 15 wt%, for example from 8 to 12 wt%.

The acidic composition of component (d) preferably further comprises one or more surfactants. Suitable surfactants will be known to the person skilled in art and include anionic, cationic, non-ionic and amphoteric surfactants. Mixtures of surfactants may be present.

Suitable anionic surfactants for use herein include sulfate and sulfonate compounds including an alkyl or alkylene chain typically of 8 to 30 carbon atoms, preferably provided as an alkali metal or ammonium salt. Substituted ammonium salts may be used, for example tetraalkyl ammonium salts. Examples of suitable anionic surfactants include ammonium lauryl sulfate, alkyl ammonium lauryl sulfates, sodium lauryl sulfate, sodium laureth sulfate, sodium myreth sulfate and sodium dodecyl benzene sulfonate.

Suitable amphoteric surfactants include betaines and sultaines. Suitable betaines include alkyl betaines, for example cetyl betaine, lauryl betaine, stearyl betaine and behenyl betaine. Examples of suitable amphoteric surfactants include cocoamido propyl betaine, lauramido propyl betaine, cocamidopropyl hydroxysultaine and lauryl hydroxysultaine.

Suitable cationic surfactants for use herein include quaternary ammonium salts including one or more long alkyl or alkenyl chain typically of 8 to 30 carbon atoms, preferably provided as a chloride or bromide salt. Examples of suitable cationic surfactants include benzethonium trimethyl ammonium chloride, dimethyl dioctadecyl ammonium chloride, cetyl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride and beheneth trimethyl ammonium chloride. Suitable non-ionic surfactants for use herein include alkoxylated and polyalkoxylated compounds and fatty acids and amines including one or more hydroxy alkyl substituents. Examples of suitable non-ionic surfactants include cocamide monoethanolamine, cocamide diethanolamine and polysorbate compounds.

Preferred surfactants for use in the composition of component (d) include sodium dodecylsulphonate, sodium laureth sulphate, sodium lauryl sulphate, cetyl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride, beheneth trimethyl ammonium chloride, tetra methyl ammonium lauryl sulfate, tetra ethyl ammonium lauryl sulphate, tetra methyl ammonium stearyl sulfate, tetraethyl stearyl ammonium sulfate, lauryl betaine, cetyl betaine, stearyl betaine, cocamido propyl betaine, cocoamide monoethanolamine, cocamide diethanolamine.

In preferred embodiments the composition of component (d) comprises from 5 to 30 wt% surfactants.

Suitably the composition comprises a mixture of surfactants. Preferably it comprises a mixture of anionic, amphoteric and nonionic surfactants, for example a mixture of sulfates, betaines and non-ionic fatty amide derivatives.

Suitably the composition may further include a cosolvent. Preferred cosolvent are water miscible solvents for example monohydric and polyhydric alcohols.

The composition of component (d) may comprise one or more further ingredients, for example those typically found in shampoo compositions. Such ingredients include surfactants, thickeners, fragrances, colourants, preservatives, conditioning agents, cosolvents and chelating agents. Examples of such ingredients may be found on the INCI list.

The composition of component (d) is preferably an aqueous composition. Suitably it comprises 50 to 99.9 wt% water. It may comprise from 70 to 99 wt%, suitably 90 to 98 wt% water. Preferably it comprises from 50 to 80 wt% water.

The composition of component (d) is preferably in the form of a viscous liquid or gel. It suitably has a consistency similar to that of shampoo and is used in a similar manner.

In some preferred embodiments the composition of component (d) is based on a standard shampoo formulation comprising an aqueous mixture of surfactants and optional excipients and which further comprises from 5 to 15 wt% of a reducing acid. Component (d) may suitably be included in the composition of the present invention in unit dose form. Thus in some preferred embodiments the kit of the present invention comprises component (d) in an amount sufficient for use in a single colour removal event, for example to remove colour from a single head of human hair.

The kit of the present invention preferably comprises from 1 to 100g component (d), preferably from 10 to 70g, more preferably from 20 to 50g, suitably from 25 to 35g.

Component (e) of the kit of the present invention comprises an oxidising composition. Any suitable oxidising composition may be used. Preferred oxidising compositions are those including hydrogen peroxide.

Preferably the composition comprises at least 0.01 wt% hydrogen peroxide, more preferably at least 0.05 wt%, suitably at least 0.1 wt%, for example at least 0.2 wt% or at least 0.3 wt%. The composition may comprise up to 10 wt% hydrogen peroxide, suitably up to 7.5 wt%, preferably up to 5 wt%, suitably up to 2.5 wt%, for example up to 1 wt% or up to 0.7 wt%..

The oxidising composition of component (e) preferably further comprises one or more surfactants. Suitable surfactants will be known to the person skilled in art and include anionic, cationic, non-ionic and amphoteric surfactants. Mixtures of surfactants may be present.

Suitable anionic surfactants for use herein include sulfate and sulfonate compounds including an alkyl or alkylene chain typically of 8 to 30 carbon atoms, preferably provided as an alkali metal or ammonium salt. Substituted ammonium salts may be used, for example tetraalkyl ammonium salts. Examples of suitable anionic surfactants include ammonium lauryl sulfate, alkyl ammonium lauryl sulfates, sodium lauryl sulfate, sodium laureth sulfate, sodium myreth sulfate and sodium dodecyl benzene sulfonate.

Suitable amphoteric surfactants include betaines and sultaines. Suitable betaines include alkyl betaines, for example cetyl betaine, lauryl betaine, stearyl betaine and behenyl betaine. Examples of suitable amphoteric surfactants include cocoamido propyl betaine, lauramido propyl betaine, cocamidopropyl hydroxysultaine and lauryl hydroxysultaine.

Suitable cationic surfactants for use herein include quaternary ammonium salts including one or more long alkyl or alkenyl chain typically of 8 to 30 carbon atoms, preferably provided as a chloride or bromide salt. Examples of suitable cationic surfactants include benzethonium trimethyl ammonium chloride, dimethyl dioctadecyl ammonium chloride, cetyl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride and beheneth trimethyl ammonium chloride. Suitable non-ionic surfactants for use herein include alkoxylated and polyalkoxylated compounds and fatty acids and amines including one or more hydroxy alkyl substituents. Examples of suitable non-ionic surfactants include cocamide monoethanolamine, cocamide diethanolamine and polysorbate compounds.

Preferred surfactants for use in the composition of component (e) include sodium dodecylsulphonate, sodium laureth sulphate, sodium lauryl sulphate, cetyl trimethyl ammonium chloride, stearyl trimethyl ammonium chloride, beheneth trimethyl ammonium chloride, tetra methyl ammonium lauryl sulfate, tetra ethyl ammonium lauryl sulphate, tetra methyl ammonium stearyl sulfate, tetraethyl stearyl ammonium sulfate, lauryl betaine, cetyl betaine, stearyl betaine, cocamido propyl betaine, cocoamide monoethanolamine, cocamide diethanolamine.

In preferred embodiments the composition of component (e) comprises from 5 to 30 wt% surfactants.

Suitably the composition comprises a mixture of surfactants. Preferably it comprises a mixture of anionic, amphoteric and nonionic surfactants, for example a mixture of sulfates, betaines and non-ionic fatty amide derivatives.

Suitably the composition may further include a cosolvent. Preferred cosolvent are water miscible solvents for example monohydric and polyhydric alcohols.

The composition of component (e) may comprise one or more further ingredients, for example those typically found in shampoo compositions. Such ingredients include surfactants, thickeners, fragrances, colourants, preservatives, conditioning agents, cosolvents and chelating agents. Examples of such ingredients may be found on the INCI list.

The composition of component (e) is preferably an aqueous composition. Suitably it comprises 50 to 99.9 wt% water. It may comprise from 70 to 99 wt%, suitably 90 to 98 wt% water. Preferably it comprises from 50 to 80 wt% water.

The composition of component (e) is preferably in the form of a viscous liquid or gel. It suitably has a consistency similar to that of shampoo and is used in a similar manner.

In some preferred embodiments the composition of component (e) is based on a standard shampoo formulation comprising an aqueous mixture of surfactants and optional excipients and which further comprises from 0.1 to 2 wt% of hydrogen peroxide. Component (e) may suitably be included in the composition of the present invention in unit dose form. Thus in some preferred embodiments the kit of the present invention comprises component (e) in an amount sufficient for use in a single colour removal event, for example to remove colour from a single head of human hair.

The kit of the present invention preferably comprises from 1 to 100g component (e), preferably from 10 to 70g, more preferably from 20 to 50g, suitably from 25 to 35g.

The kit of the present invention comprises five compositions which can be used to remove colour from dyed hair. Suitably the kit further comprises instructions for using the compositions. The kit may comprise further components, for example a disposable cap. It may optionally include apparartus for mixing the compositions and or applying to the head. For example it may include a mixing bowl, spoon, spatula, brush or disposable gloves. Compositions (a), (b), (c), (d) and (e) are included in the kit in suitable packaging. They are suitably packaged separately. Any suitably packaging may be used and suitable packing will be known to the person skilled in the art.

The compositions may be packaged in bottles, jars, tubes, sachets or boxes. The packaging or each compositon may be the same or different. In some embodiments one or more of the compositions may be packaged in an inert atmosphere, or in a vacuum.

Suitably the kit of the present invention comprises an outer packaging. The kit therefore preferably provides a packaged colour removal product which contains all components necessary for a single colour removal event, for example the removal of colour from a single head of hair.

According to a second aspect of the present invention there is provided a method of removing colour from dyed hair using the kit of the first aspect, the method comprising the steps of:

(i) preparing a colour removal composition by admixture of components (a), (b) and (c);

(ii) contacting the hair with the colour removal composition;

ii) contacting the hair with component (d); and

iv) contacting the hair with component (e).

Suitably steps (i) to (iv) are carried out sequentially. In step (i) components (a), (b) and (c) may be mixed together in any order. Suitably all of the components are added to a suitable container and then mixed together thoroughly, for example by stirring. Step (ii) is preferably carried out less than an hour after step (i), preferably les than 30 minutes, more preferably less than 20 minutes, suitably less than 10 minutes. Step (i) is preferably carried out immediately prior to step (ii).

In step (ii) of the method of the second aspect the composition is suitably applied to the hair and maintained on the head at a temperature of from 10 to 75 ^S C, preferably from 20 to 60 ^S C, more preferably from 30 to 50 ^S C.

When using temperatures above ambient temperature a suitable hood can be employed to achieve the required temperature.

Suitably the composition is contacted with the hair in step (ii) for a period of at least 30 seconds, preferably at least 1 minute, for example at least 5 minutes. In step (a) the composition may be contacted with the hair for a period of up to 2 hours, suitably up to 1 .5 hours, for example up to 1 hour. The time for which the composition should be left in contact with the hair will depend on the starting colour of the hair. For hair that has been dyed with a light colour, colour removal can usually be achieved within 1 0 to 20 minutes. For black hair up to 60 minutes may be needed. The extent of the colour removal can be monitored by visual inspection. The composition prepared in step (i) and used in step (ii) is suitably in the form of a cream, gel or paste. It suitably has a consistency that enables it to be readily applied to and spread throughout the hair but then stays on the hair and does not run off.

In step (ii) the composition may be contacted with the hair by any suitable means. Suitably it is brushed on to the hair to provide an even coverage. Suitably the composition used in step (ii) is contacted with the hair using a liquor ratio of from 5:1 to 1 :1 , preferably from 4:1 to 3:1 , suitably about 2.5:1 . By this we mean that 2.5 parts by weight of the composition is applied for each part by weight of hair used. Step (iii) of the method of the present invention involves contacting the hair with an acidic composition. In the method of the second aspect of the present invention steps (ii) and (iii) are carried out sequentially. Suitably there is no rinsing step between steps (ii) and (iii), that is the composition applied in step (ii) is not rinsed from the hair with water prior to step (iii). Thus step (iii) of contacting the hair with an acidic composition involves applying the acidic composition to hair which remains in contact with the composition applied in step (ii). Following step (ii) excess composition may be brushed from or squeezed out of the hair but preferably it is not removed by rinsing with water. In step (iii) the acidic composition is preferably liberally applied to the hair and spread thoroughly throughout the hair. This may be done manually using the fingers as one might spread shampoo throughout the hair.

Preferably after application of the acidic composition it is allowed to remain in contact with the hair for a period of at least 30 seconds, suitably at least 1 minute, preferably at least 2 minutes, preferably at least 3 minutes, for example at least 4 minutes. The composition may be allowed to remain in contact with the hair for up to 20 minutes, suitably up to 15 minutes, preferably up to 10 minutes, more preferably up to 8 minutes, for example up to 6 minutes. Step (iii) may suitably be carried out at ambient temperature. However it has been observed to be more efficient at higher temperatures.

Following step (iiii) the composition may be rinsed from the hair, for example with warm water. Thus there is suitably a rinsing step between step (ii) and step (iii).

In step (iv) the oxidising composition is preferably applied liberally to the hair and spread thoroughly throughout the hair. This may be done manually using the fingers as one might spread shampoo throughout the hair. In step (iv) the oxidising composition is suitably left in the hair for a period of 10 seconds to 10 minutes, preferably 20 seconds to 2 minutes, suitably up to 5 minutes and then rinsed from the hair thoroughly with hot water.

Hair treated according to the method of the present invention suitably has a colour that closely matches its colour prior to dyeing. In the case of a very strong colour or if the hair is very porous, the method may be repeated.

The kit of the present invention may be used to remove colour from hair that has been dyed using variety of different classes of hair dyes. For example the kit can very effectively remove colour from hair dyed using the compounds and methods described in the applicant's applications WO 2010/032034 and WO 2009/1 12858. Furthermore the kit of the present invention also reliably removes colour from hair that has been oxidatively dyed and does not cause significant damage to the hair or use dangerous chemicals. The invention will now be further described with reference to the following non-limiting example.

Example

A kit of the present invention was prepared comprising the following components, each packaged in individual bottles:

Composition A

12g magnesium acetate

21 g water

Composition B

12g formamidine sulfinic acid

Composition C

200g of a composition comprising:

Composition D A shampoo composition comprising water, propylene glycol, glycerin, preservatives, perfume, 10 wt% ascorbic acid and approximately 20 wt% of surfactants (anionic, amphoteric and nonionic).

Composition E A shampoo composition comprising water, propylene glycol, glycerin, preservatives, perfume, 0.5 wt% hydrogen peroxide and approximately 18 wt% of surfactants (anionic, amphoteric and nonionic). The bottles of compositions A, B and C were opened and the whole contents poured into a bowl. The mixture was stirred to form an even distribution and the composition was then brushed onto bleached blonde hair that had been dyed brown. The hair was maintained at 40 ^S C for 30 minutes after which time the hair appeared blonde. Excess composition was squeezed from the hair and then composition D was spread through the hair without rinsing. After 5 minutes the hair was rinsed with warm water. Composition E was then spread through the hair in the manner of a shampoo and rinsed away with water. The hair was dried and appeared to have the same colour as before it was dyed with no observable damage.