Asma bint Abi Bakr (may Allah be pleased with her) said: I heard a woman asking him (peace and blessings be upon him) what a woman should do with her clothes when she becomes pure from her menstruation. He (peace and blessings be upon him) said: "If she sees blood on them, she should scrape it and wash it, sprinkle water over the rest of her clothes, and pray."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4107