It was narrated that 'Ali bin Abu Talib said:
"I broke one of my forearms and I asked the Prophet about that. He told me to wipe over the bandages." (Maudu')Another chain with similar meaning. (FR)
English reference (FR): Vol. 1, Book 1, Hadith 657 (FR)
Arabic reference (FR): Book 1, Hadith 701 (FR)