On the expedition of Tabuk the Messenger of Allah (ﷺ) came to a household and, seeing a bucket hanging, asked for water. They said: Messenger of Allah, the animal died a natural death. He replied; Its tanning is its purification.
Sunan Abi Dawud Book 34, Hadith 106
← Previous Hadith The Prophet (ﷺ) ordered that the skins of the animals which had died a natural death should be used when they are tanned.

Sunan Abi Dawud Book 34, Hadith 105 Next Hadith → I had some sheep at Uhud, and they began to die. I then entered upon Maymunah, wife of the Prophet (ﷺ), and mentioned it to her. Maymunah said to me: If you took their skins and made use of them, (that would be better for you). She asked: Is that lawful? She replied, Yes. Some people of the Quraysh passed by the Messenger of Allah (ﷺ) dragging a sheep of theirs as big as an ass. The Messenger of Allah (ﷺ) said to them: Would that you took its skin. They said: It died a natural death. The Messenger of Allah (ﷺ) said: Water and leaves of the mimosa flava purify it.

Sunan Abi Dawud Book 34, Hadith 107