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
← Previous Hadith I heard a woman asking the Messenger of Allah (ﷺ): What should any of us to with her clothe (in which she menstruated) when she becomes purified ? Can she pray in that (clothe) ? He said: She should see; if she finds blood in it, she should scratch it with some water and (in case of doubt) sprinkle upon it (some water) and pray so long as she does not find (any blood).

Sunan Abi Dawud Book 1, Hadith 360 Next Hadith → 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