The skins may be soaked in petroleum ether in a closed tank or pan for two or three days, removed, wrung out, dried, brushed, and combed; or they may be well brushed all over with a mixture of bran and benzoline, and, after drying, brushed and combed. Another method is to brush the skins with a solution of olive-oil soap in methylated spirit, followed by sponging with clean methylated spirit.