Sunan at-Tirmidhi (Jami-al-Tirmidhi), Chapter: Taharah (Purification)

narrated that a guest came to Sayyidah Aisha (RA). She instructed that a yellow bed?sheet be given to him. He slept on it and had a nocturnal dream. He was ashamed to return the bed?sheet while it had traces of sexual dreams. He immersed it in water and then returned it. Sayyidah Aisha (RA) said, "Why did he spoil our bed?sheet. It was enough for him to scratch it out with his fingers. I used to scratch it out from the garments of Allah's Messenger (SAW) with my fingers." [Ahmed24213, 24905, Muslim 290, Abu Dawud 371]