Sunan Ibn Majah Book 1, Hadith 205
"The Messenger of Allah came to us, and we brought water out to him in a vessel of brass, and he performed ablution with it."
"The Messenger of Allah said: 'There is no Muslim who performs ablution and does it well, then says: Ashhadu an la ilaha illallah, wa ashhadu anna Muhammadan `abduhu wa rasuluhu (I bear witness that none has the right to be worshipped but Allah, and I bear witness that Muhammad is His slave and Messenger),' (except that) eight gates of Paradise will be opened for him, and he will enter through whichever one he wants.'"
She had a tub of brass. She said: "I used to comb the hair of the Messenger of Allah in it."