Most auto parts places (Pep Boys, Autozone, Checker, etc) carry a variety of plastic polishing products. I've used several of Meagars (spelling) products and they work well, even on heavily scratched windscreens. They come in a variety of "grits" from course to very fine. The fine end of the spectrum works very well on MC windscreens. They even have a product that is very similar to Plexus, which is a good finishing product, but doesn't do much for scratch removal.
I bought my fairing with a big scratch in the windshield at a discounted price, so I searched for something to take the scratch out. I was at a car show in Wis when I came across a 3M booth and told the vendor my problem. He sold me a bottle of 3M Plastic Polish designed for clear and colored plastics. It was $7 for a 8oz bottle. It is just like a wax. I tried it and the scratch came right out. Saved myself $75 because of the scratch and took it out for $7. Not a bad deal!! Anyway, here is the part number if you are interested...051131. Unfortunately I don't know the depth of your scratches, but if they aren't gouges, this should take them out. Worked for me! 8)