Headlights don't have a clear coat on them from the factory, but it is sometimes applied to protect the headlights. In most cases, the clear coat eventually becomes dull, yellow or flakey and causes more problems than the original dirty headlights. Remove clear coat from headlights to restore them to their original clarity. Once it has been removed, you can use a plastic sealer to protect the headlights from UV rays and oxidation. This can keep them more clear than a layer of clear coat.
Place several strips of masking tape on the painted surfaces surrounding the headlights to protect the paint -- these include the edges along the hood, fenders and front bumper cover that are painted. Any sections of the chrome trim should also be protected.
Sand the headlights using 800-grit sandpaper to remove the old clear coat. Hold the sandpaper flat on the surface and sand the entire headlight evenly. Keep the sandpaper wet with water to prevent buildup from scratching the headlights.
Go over the headlights again using 1000-grit sandpaper and water, in the same way as when using the 800-grit paper. This smooths the scratches made by the previous sandpaper and removes any remaining clear coat.
Sand the headlights once again using 2000-grit sandpaper and water to completely smooth the headlights. The headlights should look dull and cloudy, but there should be no more clear coat on them. Rinse the headlights and allow them to dry completely.
Apply plastic lens cleaner and polish to the headlights, using a clean cotton towel. Work the cleaner in small circles and cover the entire headlight. Repeat this step on each headlight several times for the best results. The headlight should look more clear as each coat is applied and worked into the surface.
Use a microfiber towel to apply a final coat of the plastic lens cleaner and polish to the headlights. This shines the headlight's surface to make it look like new.