Musnad Ahmad 1168:7

'Abd al-Rahman ibn Mahdi narrated to us, he said: Sufyan narrated to us, from Thabit, from 'Adi ibn Dinar, the freed slave of Umm Qays, from Umm Qays bint Mihsan, she said: I asked the Messenger of Allah, peace and blessings of Allah be upon him, about menstrual blood that gets on a garment. He said: "Wash it with water and lotus leaves (sidr), and rub it with a rib."