Patent ID: 7404826

Claim:
A process for removing one or more horny substances from hide, pelt or skin of a dead animal, wherein the hide, pelt or skin is treated in aqueous liquor comprising one or more compounds of the formula I or their corresponding alkali metal or alkaline earth metal salts or ammonium or phosphonium salts: R 1 is selected from the group consisting of hydrogen and C 1 -C 12 -alkyl, unsubstituted or substituted by one or more S—H or O—H groups; X 1 to X 4 are identical or different and are selected from the group consisting of hydrogen, C 1 -C 4 -alkyl, O—H, S—H and N—HR 2 , R 2 is hydrogen or C 1 -C 12 -alkyl or a C 1 -C 4 -alkyl-C═O group, at least one radical X 1 to X 4 being S—H when R 1 contains at least one sulfur atom and at least two radicals X 1 to X 4 being S—H when R 1 contains no sulfur atom, wherein one or more basic alkali metal compounds are added and lime is absent, and wherein said process is carried out at a pH value of from 7 to 14.