Not, alas, an academic question

If one happened to have a pile of clothing on the floor, and one discovered belatedly that cat or cats had peed on it and the pee had dried, is there anything that will remove the stain? The enzyme stuff will remove the smell, but if it's permanently discolored, there's a bunch of stuff that's going to be a dead loss.

Mostly in cotton clothing, but some rayon and (alas) silk.

The cats are hissing at each other right now; I'm starting to think I may have to find a new home for one of them. They're great individually, and they get along half the time, but the other half is a problem that isn't going away.