Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that the Prophet (peace and blessings be upon him) intended to perform ablution from a water-skin, and it was said to him (peace and blessings be upon him): This is (the hide of) a carcass. He (peace and blessings be upon him) said: "Its tanning removes its filth (or its impurity, or its uncleanness)." This hadith is sahih (authentic) and there is no hidden defect ('illah) in it, but the two Shaykhs (Bukhari and Muslim) did not record it.