Musnad Ahmad 32:1275

'Abd al-Samad narrated to us, Hammad narrated to us, from Thabit, from Anas: "When the Messenger of Allah (peace and blessings of Allah be upon him) intended to shave his head, Abu Talhah took hold of one side of his head. When the barber shaved it, he took it and brought it to Umm Sulaym, and she began putting it into her perfume."