i haven't but would have thought the flexible vinyl paint would be best, no? have you tried cleaning it with one of those 'magic eraser' things? they're excellent at getting marks off vinyl.
Try wiping over with a solution of Sugar soap, great for removing grease and nicotine staining. Painting , you might live to regret it... sort of last resort before selling IMHO
i think theres a spray paint out there, my mate used to do all his mini headlings in black...looked great, as said above clean and de grease first
