How to act when relieving oneself - Section 3 Mishkat al-Masabih 375
Translation
Ibn Mas'ud told that when the deputation of the jinn came to the Prophet that said, “Messenger of God, forbid your people to cleanse themselves with bone, animal dung, or charcoal, for in them God has provided provision for us.” So God’s messenger forbade them to do that. Abu Dawud transmitted it.