Sayyiduna Anas (may Allah be pleased with him) narrates: I was walking along with the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said to me: O my son! Bring me water for ablution from this house! I said (to the people of the house): The Messenger of Allah is asking for water for ablution. That man said: Tell him that our (leather) bucket is made from the hide of a dead animal. The Prophet (peace and blessings be upon him) said: Ask them whether they had tanned it. They replied (when asked): Yes! The Prophet (peace and blessings be upon him) said: Its tanning is the means of its purification.
Imam Abu Ya'la recorded this narration; its chain mentions that Durust bin Ziyad narrated it from Yazid al-Raqashi, and there is disagreement about using either of them as evidence.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1090