It is narrated from Sayyiduna Salamah bin al-Muhabbiq (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) came to a woman and asked for water. A waterskin was brought, and he (peace and blessings be upon him) drank. It was said: O Messenger of Allah, this is (made from) the skin of a dead animal. The Messenger of Allah (peace and blessings be upon him) said: "Tanning a hide purifies it."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6312