Musannaf Ibn Abi Shayba 1:2076

Waki’ narrated to us, from ‘Ali ibn Mubarak, from Karima bint Hammam, who said: I heard ‘Aisha—and she was asked about menstrual blood that gets on a garment—and she said: "Wash it." She said: "I washed it, but its trace did not go away." She said: "Wash it, for water is a purifier."