The possibility of using the unutilizable acetophenone-containing industrial waste in the alkylthiomethylation reaction of ketones for demercaptanization of hydrocarbon feedstock and regeneration of sulfide-alkaline liquors was shown. The reaction proceeds for 0.5-5 h at 20-50 degreesC and a ketone: formaldehyde : sodium hydroxide : ethanol molar ratio of 2 : 2 : 0-2 : 0-2 per mole of sulfur. The conversion of active sulfur-containing compounds was as high as 97-100% with simultaneous production of practically useful gamma -oxoalkylsulfides.