In a method of removing carbonyl sulfide from propylene by hydrolysis over a catalyst comprising platinum sulfide on alumina, the improvement comprising regenerating the catalyst by contacting the catalyst with a solvent for polypropylene under conditions such that any polypropylene on the catalyst will be readily dissolved. Specifically, the propylene is passed through, successively, a C.sub.3 -splitter, a heater, the platinum sulfide catalyst bed, and a topping still where resulting H.sub.2 S and CO.sub.2 are separated from the purified propylene. A preferred solvent is liquid propylene.