From Sahih Muslim (Hadith 809):
Ibn Abbas reported:The Messenger of Allah (ﷺ) happened to pass by a goat thrown (away) which had been in fact given to the freed slave-girl of Maimuna as charity. Upon this the Messenger of Allah (way peace he upon him) said: Why did they not get its skin? They had better tan it and make use of it
Reference: Muslim 809