When it comes to sanding headlight lenses, you'll want to use very fine grit wet/dry sandpaper. This is because using too coarse an abrasive on plastic could cause damage or even cracks in the lens cover itself. We recommend starting with a 1000-grit paper and then moving up to 1500-grit or 2000-grit if necessary. Then finish off by polishing with some rubbing compound and buffing out any scratches with wax. The key is working slowly and carefully so as not to damage the lens while still getting rid of all those cloudiness issues.