if they're plastic and the scratches aren't deep then you can probably get them out with a fine cut rubbing compound. A decent auto body supplier will sell similar compounds made just for plastic. If the scratches are deep then they're rpobably there for good.
I say Plexus too- that works good.
If that doesnt help, theres a company called "Janvil" that makes a glass scratch repair kit and a plastic scratch repair kit.... You can buy a sampler pack for like $15 from their website.. if you have some patience, it works pretty good. I gotta use it on my car headlights this summer.