DS had a nosebleed in bed a few weeks ago and didn't tell me. It didn't get on his sheets, but it got on the underside of his comforter. I found it several days after it had happened. Washing it with Shout didn't seem to touch it. My grandmother suggested a 50/50 water and bleach mix, dabbed on and then rinsed immediately. I did this and it worked great! Since your capris are white, I think it should work on them, too. Good luck!