I just restored my ty250 , What I did with the side cover is i sanded with wet/dry sandpaper ( wet)..I had some scratch's on it. So i started out with 220 grit.But if you dont have any bad scratchs then , i would start out with with a higher grit,like 400 and work up to 1200.or even higher untill you get the results that you want. Then polish it with a plastic polish.The downside is it will make the plastic thinner. Have fun and hope you get it worked out.