Polycarbonate headlight lenses become yellowed and dull with time due to tiny scratches that collect dirt and oil, and also due to sun exposure. Ultraviolet light also reacts with the polycarbonate and turns it yellow. Often, the surface of the lens may be sanded down, sealed and polished for a sparkling, new-looking headlight. If the damage is too extensive, an expensive replacement may be necessary. Complete headlight cleaning kits can be purchased for ease of use.
Wash the lens and surrounding area thoroughly to remove all surface dirt and grime, and dry with a clean rag.
Apply painter's tape to the paint surrounding the headlight to protect it from being scratched by the sandpaper.
Soak the pieces of sandpaper for 15-20 minutes in the bucket of soapy water.
Put on your gloves.
Sand the headlight lens with the 600-grit sandpaper, using only side-to-side strokes. Be thorough, rinsing often to take note of your progress.
Sand with 800-, 1200- and finally, 2000-grit sandpaper until the surface has a dull appearance, is clear, and has no noticeable imperfections like pits or gouges.
Reglaze the lenses by using wool or foam pads and a drill or buffer on the lens.
Use a commercial polish on the wool or foam pad as your final polishing step. Buff until the headlight lens looks like new.
