Musannaf Ibn Abi Shayba 1:1172

Waki’ narrated to us, from Isma’il bin Abi Khalid, from his father, who said: I had a debt owed to me by Al-Husayn bin ‘Ali, so I came to him to demand payment. I found that he had come out of the bathhouse, and the traces of henna were on his fingernails, and a slave girl of his was scraping the traces of henna off him with a glass vial.