I heard the Messenger of Allah ﷺ say, "Any hide that has been tanned has become pure."
حدثنا عبد الرحمن عن سفيان عن زيد بن أسلم عن عبد الرحمن بن وعلة
سمعت رسول الله ﷺ يقول أيما إهاب دبغ فقد طهر
Its isnad is sahih, and it is a repetition of 1895, and an abridgment of 2435 and 2252. At the end of the hadith there is a remark from Shubah that he used to check on his companions, and that he asked one day about Shababa bin Sawwar Fazari, one of his students. I do not know why this remark appears here.