To provide a method for selectively removing combustion product from surface of parts of a gas turbine after the long term exposure in the high temperature oxidizing and corrosive environment of exhaust gas of the gas turbine without affecting metal or film of adjacent substrates which are not altered, and a material composition therefor.

Loose contamination is removed from the surface of parts of the gas turbine engine, a moldable reactive metallic composition including more than one kinds of metals having affinity with oxygen selected from the group consisting of Al, Si, Ti and Zr is applied to the corrosion part which is heated to about 1800-2000° F in a non-reactive environment to generate the reaction between the combustion product and the reactive metal. Thereby, the combustion product of the corrosion part on the surface if decomposed to occur a by-product, which is cooled thereafter. The by-product can be removed optionally from the surface of parts.