This is probably awful, but I was wondering if it would be a good idea to spray paint yarn. I have cotton crochet thread in mind, and I would crochet or knit something before painting it. I'm sure the paint would rub off, but do you think I could spray some kind of sealant on there so it wouldn't rub off too badly? If it caused the knitted piece to become stiff, that wouldn't be so bad, it might add some interesting possibilities (perhaps some structural integrity for knit/crochet jewelry or sculpture).
What do you guys think?