I have fixed windscreens and removed the scratches so they were completly gone when done
I start by wet sanding down the scratches, depending on how deep they are, I am start out with 1500 wet and then work my way up to 2000 then 2500 then polish with a wet 3000 grit paperon a small buffer, I then use a polishing compound on my buffer and then a finish polish on the rest of the shield. I have taken out some nasty scratches, the draw back is that I use a lot of different products to do it right. I already have all this stuff for wet sanding and buffing clear coat so it is a zero investment for me. I can honestly think of no one or two step process that will give you perfect results but if you go to Wal Mart and pick up some of the fine grit paper that they have and then get a leveling compound for clear coat that is meant to be put on by hand I bet you could make your shield look a lot better for a limited amount of money.