You can buy at an automotive finish supply like Sherwin-Williams up to 2500 grit silicon carbide paper (which will also remove scratches from glass by the way.) Then Trizact pads in 3000 and 5000 grit. Then you can use your polishing compounds of choice on plastics. I use 3M Micro-fine compound (blue) and Glazing compound (yellow) for a scratch-free finish. For glass, cerium oxide powder, mixed with water in a slurry, on a felt or leather pad.