Anas said, "Um Sulaim used to spread a leather sheet for the Prophet (ﷺ) and he used to take a midday nap on that leather sheet at her home." Anas added, "When the Prophet (ﷺ) had slept, she would take some of his sweat and hair and collect it (the sweat) in a bottle and then mix it with Suk (a kind of perfume) while he was still sleeping. "When the death of Anas bin Malik approached, he advised that some of that Suk be mixed with his Hanut (perfume for embalming the dead body), and it was mixed with his Hanut.

Sahih al-Bukhari Book 79, Hadith 55