Well I haven't tried this on a dust cover, but it works for airplane windows. Micro-Mesh cushioned abrasives. They come in sample packs with grit as fine as 12000 for hand rubbing and velcro backed pads for random orbital sanders to 3000 I think. You can get a finish like glass, but it's a lot of rubbing if you have to start below 1000. I got mine from a Woodcraft store, but I think they no longer carry them. I did a quick search and found a web site with individual sheets, so it's still available somewhere.
My guess would be you need most of the grades above 3000 unless your cover is badly scratched. Do a test on a piece of acrylic before you go after your dust cover because you may not want to go through the effort once you get started.
You can also get the same results with liquid polishes and a buffing wheel once you get close to smooth with a lot less elbow grease.
Good luck and let me know how it turns out.
