I used to apply 3M Headlight/Plastic Cleaner then 3M Headlight/Plastic Polish to the headlights on my G35 with pretty good results. I never sanded those, just used a terry cloth to rub in the 3M goop. Worked pretty well, though I generally had to do it after each wash. (Add that to cladding dressing, tire black, and glass cleaner and there goes your entire day )