Musannaf Ibn Abi Shayba 16:545

Abu Bakr narrated to us, he said: Hushaym narrated to us, he said: Abu Bishr informed us, from Ikrimah, that the Messenger of Allah (may Allah bless him and grant him peace) passed by a sheep belonging to Sawdah bint Zam'ah. He said: "Why do you not make use of its hide? For its tanning is its purification."