Al-Aliyah, daughter of Subay', said: 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.
Benefits and Issues: From the hadiths regarding the prohibition of the skins of predatory animals in the chapter following this one, it is established that only the skins of lawful (halal) animals become pure by tanning, not the skins of unlawful (haram) animals and predators.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 4126
´It was narrated from Maimunah, the wife of the Prophet, that:` some men of Quraish passed by the Messenger of Allah dragging a sheep the size of a donkey. He said to them: "Why don't you take its skin?" They said: "It is dead meat." The Messenger of Allah said: "Purify it with water and Qaraz."
Hafiz Muhammad Ameen
This hadith indicates that, for tanning the raw hide of a dead animal, water and the bark of the acacia tree (kikar) are necessary, or any such chemical possessing similar properties that removes the odor and moisture from the hide—its use is also permissible. The objective is tanning (dibaghah).
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 4253
Narrated Maimuma: Narrated (rad): Some people dragging a (dead) goat passed by the Prophet (ﷺ). He told them, “Had you better taken its skin”. They said, “It is dead”. He said, “Water and the leaves of the Acacia tree will purify it”. [Reported by Abu Da’ud and An’Nasa’i].
Shaykh Safi ur-Rahman Mubarakpuri
Lexical Explanation: «اَلْقَرَظُ» is with a fatha on both the "qaf" and the "ra". It refers to the leaves and bark of the acacia tree. At that time, it was well-known and common among the Arabs to use it for tanning leather.
Benefit: This hadith and the two preceding ones indicate that the hides of dead animals become pure through tanning. It is permissible to make vessels from them and to perform ablution (wudu) and similar acts using those vessels.
Source: Bulugh al-Maram: Commentary by Safiur Rahman Mubarakpuri, Page: 18