Acrylic Buffer?

I have and use this kit, it works great to restore hazy headlight plastic lenses too.

You might be able to find it, or something comparable elsewhere too. It's basically multiple grades of special wet/dry sandpaper that you use in succession to sand down the scratches and then use a final polish compound to buff out the really fine scratches.

You can also pick up a product called Novus Plastic Polish at Delvies plastic or Region Supply that will buff and polish fine scratches it's a lot like a car wax in a way, but if you can feel the scratches with your fingernail, you'll want to use a sandpaper buffing kit.

Good luck!