From Sahih Bukhari (Hadith 227):
Narrated Asma':A woman came to the Prophet (ﷺ) and said, "If anyone of us gets menses in her clothes then what should she do?" He replied, "She should (take hold of the soiled place), rub it and put it in the water and rub it in order to remove the traces of blood and then pour water over it. Then she can pray in it
Reference: Bukhari 227