Yeah, you can. I used to have a "Barrel of monkeys" theme all over one of my helmets that my buddy put on there. Just make sure you sand it, prime it, paint it, then MOST IMPORTANTLY... CLEAR IT. You NEED to clear coat it or it will chip. Do 2-3 coats of clear for the best results. If you can, get a clear with a flex agent in it, or it may crack, especially in colder temps.