Rub it off (with a stone), and then scratch it (with finger) by pouring water, then sprinkle water upon it.
Sunan Abi Dawud Book 1, Hadith 362
← Previous Hadith A woman asked the Messenger of Allah (ﷺ): Messenger of Allah, what do you think if the clothe of any of us smeared with the blood of menstruation; what should she do ? He said: If (the clothe of) any of you is smeared with blood of menstruation, she should scratch it; then she should sprinkle water upon it and then she may pray.

Sunan Abi Dawud Book 1, Hadith 361 Next Hadith → I asked the Prophet (ﷺ) about the blood of menstruation on the clothe. He said: Erase it off with a piece of wood and then wash it away with water and the leaves of the lote-tree.

Sunan Abi Dawud Book 1, Hadith 363