Musannaf Ibn Abi Shayba 1:1653

'Abd al-Wahhab al-Thaqafi narrated to us, from Yunus, from al-Hasan, that he used to dislike performing *istinja* (cleaning oneself after relieving oneself) with a stone that a man had already used for *istinja*, or with dung, or the excrement of an animal, or with a bone.