I did 8 set of truck head lights had to cut UV seal out . I dry sand with 150 grit on some on some 220 grit to start then 300, 400, 500, 800 all dry then 1000, 1500, 2000, 2500, all wet then Abralon 3000, 4000, moist. The n polished and UV seald. Takes time but it works.