Musnad Ahmad 1156:252

Ahmad ibn al-Hajjaj narrated to us, he said: Abd al-Aziz ibn Muhammad narrated to us, from Muhammad ibn Tahla, he said: I said to Abu Salamah: "Your foster brother, Sulaym, does not perform ablution (wudu) for what fire has touched." He said: So he struck the chest of Sulaym and said: "I bear witness regarding Umm Salamah, the wife of the Prophet, may Allah bless him and grant him peace, that she used to bear witness that the Messenger of Allah, may Allah bless him and grant him peace, used to perform ablution for what fire has touched."