It is narrated from Hazrat Salamah (may Allah be pleased with him) that once the Prophet (peace and blessings be upon him) passed by a house in whose courtyard a water skin was hanging. The Prophet (peace and blessings be upon him) asked those people for water to drink, so they said that it was made from the skin of a dead animal. The Prophet (peace and blessings be upon him) said, "Tanning is the purification of the skin."
Hadith Referenceمسند احمد / أول مسند البصريين / 20062
Hadith Gradingحکم دارالسلام:مرفوعه صحيح لغيره، وهذا اسناد ضعيف، والرجل المبهم هنا، جون بن قتاده وهذا مجهول