Be careful with dying mohair for too long.
I dyed some hair with Fuschia RIT, then put it in the Velvet Black Dylon, boiling for about half an hour, then left it. It's black, right? You can't dye it too dark. I looked at it a few times, couldn't see the curls. Must have floated to the bottom.
Went to get it, BLACK GOO. The fibres broke down. NOOOO!
So. Be careful.