You can get the scratches out, but it will take a lot of work. Start with sand paper that is about 600 grit, then progressively get finer and finer paper until you use 1200 or 1500 grit. After that, use a liquid polish used for plastic, like helmet visor polish. You can also use a kit for clearing up fogged up headlights from the auto part store. Like I said, it will take time. To me, it's not worth it because I know it's going to get scratched again a few rides later.
Yea after my first trip to the mud hole mine was all scratched up. Then it didn't help I was following some smaller bikes that didn't understand I wasn't trying to wedge my maverick between two trees. Anyway now they're so scratched up that the black plastics dont even shine anymore