This is the third time i've had to tint my tail lights. The first time I did it I didn't clean the taillights at all, it gave it a weird look, it also made it fade very quickly. I got around to redoing it this weekend, and this time I did it right. I knocked off some of the old paint with some 80 grit, and 600 grit sandpaper, the 80 was way too rough and left deep scratches in it, so I advise you not to use that. If I were to do it again, I'd use like a 220.