Abstract: Waste products from the chrome-tanning of hides are washed and then chopped in water, with subsequent hydrolyzation at a pH of at least 10.5 and at boiling or near-boiling temperature. The resulting suspension is filtered to yield a polypeptide solution and a cake of solids consisting essentially of chromium hydroxide. The solution is neutralized, dehydrated, cooled and filtered to provide a virtually chromium-free proteinaceous substance usable as plant or animal feed; the solids are washed, filtered and acidified to provide chromium sulfate suitable for reutilization in tanning.