The people said to Salman (may Allah be pleased with him): Your Prophet (peace and blessings be upon him) has taught you everything. He said: "Yes, the Messenger of Allah (peace and blessings be upon him) forbade us from facing the qiblah while defecating or urinating, and that any of us should clean himself (istinja) with the right hand, or that any of us should clean himself with fewer than three stones, and that one should clean himself with dung or a bone."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6057