Sunan an-Nasa'i, Hadith 4245 ⓘ
It was narrated that 'Aishah said: "The Messenger of Allah was asked about the hides of dead animals." He said: "Tanning it purifies it."
أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعْدِ بْنِ إِبْرَاهِيمَ بْنِ سَعْدٍ، قَالَ حَدَّثَنَا عَمِّي، قَالَ حَدَّثَنَا شَرِيكٌ، عَنِ الأَعْمَشِ، عَنْ إِبْرَاهِيمَ، عَنِ الأَسْوَدِ، عَنْ عَائِشَةَ، قَالَتْ سُئِلَ رَسُولُ اللَّهِ صلى الله عليه وسلم عَنْ جُلُودِ الْمَيْتَةِ فَقَالَ " دِبَاغُهَا ذَكَاتُهَا " .
also referenced under: Book 41, Hadith 24 (In-Book) & Volume 5, Book 41, Hadith 4250 (DarusSalam)