Sunan Abi Da'ud

Narrated Khuzaymah ibn Thabit: The Prophet (ﷺ) was asked about cleansing (after relieving oneself). He said: (One should cleanse oneself) with three stones which should be free from dung.Abu Dawud said: A similar tradition has been narrated by Abu Usamah and Ibn Numair from Hisham.