Minced animal hide and skin scraps (collected at a slaughter of cattle and pigs) were soaked in H(2)O to remove curing salts, limed with Ca(OH)(2) in 20 m(3) vessels, soaked with H(2)O to remove Ca(OH)(2), and macerated with diluted HCI or H(2)SO(4) at pH 6.3-6.6 for 6-8 h. Then, the skin scrap sludge was pumped to a system of tanks (4.5 m(3) each) and hydrolyzed at 60-70 degrees C and pH 6.3-6.6 to resp. polypeptides after addn. of com. 30% H(2)O(2) (0.5 L per 1000 kg of wet crude material). The d. of the soln. was checked with areometer at 50 degrees C. The process was completed when the polypeptide concn. reached 14.1%. The liq. was sepd. by centrifuging and filter pressing. The process was repeated twice by using the remaining skin pieces from the first hydrolysis in similar manner. The resulting polypeptides (yield 13.2-15.0%, related to the crude skin scraps) showed the mol. mass 40-60 kDa. The process was corm implemented and found more economically efficient than the conventional hydrolysis of gelatin.