PURPOSE: To solve the problem of used edible oil disposal which is recently becoming important in view of public hazard and environmental pollution control measures and resource utilization by establishing a process for producing extremely easily a pudding-like, waxy or solid soap consisting of a fatty acid salt from a waste edible oil.

CONSTITUTION: A waste edible oil is mixed with at least one member selected from org. acid compd. consisting of a C6 or higher org. acid which is soluble in an edible oil but becomes insoluble and forms a gel-like body when an aq. soln. or an aq. slurry soln. of a strongly alkaline compd. is added thereto, a heavy metal salt of the org. acid and a derivative of the org. acid, a surfactant and a strongly basic alkali, and the mixture is stirred for a short time without any special heating to obtain a pudding-like, waxy or solid soap wherein a fatty acid salt is a main ingredient.