Sunan Ibn Majah
629
Sahih+3

It was narrated that Asma' bint Abi Bakr said:"The Messenger of Allah was asked about menstrual blood that gets on clothing. He said: 'Rub it off, wash it and perform prayer in (the garment)

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi