I would not be worried about the dope attacking the spinner, as the plastic spinners are usually some form of nylon. I would be concerned about the paint not sticking very well. If you must paint a plastic spinner, buy a new one in white (easier to get the right color of red painting over white) wash it with dish soap, then scuff it up with 400- 600 sandpaper before painting. You could even test/practice on the "wrong" color red one first.Try not to get raw fuel on it, and don't let an electric starter anywhere near it. Or you could opt for a contrasting color plastic spinner, or a nice shiny aluminum spinner. For that matter, auto paint on an aluminum spinner would probably work best.