Sayyidah Aishah (may Allah be pleased with her) said: I remember that I used to scrape janabah off the clothes of the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) would not wash that spot.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4173