Clouded, yellowing headlight lenses are an eyesore and embarrassment on any car. The cause of the yellowing is prolonged exposure to sunlight, air pollution, dust, and other harsh environmental contaminants. But the good news is that the damage to these plastic lenses is usually only surface deep, and by following our six-step procedure, you can have your headlights back to a shine in no time. To demonstrate, we used a Subaru headlight that was damaged when brake cleaner was applied by a "friend" who had mistaken the plastic for a glass lens.
2. Thoroughly clean any debris from the headlight lens with a commercial plastic lens cleaner or soap and water and wipe dry using a clean rag or shop towel.
3. To remove oxidation or melted plastic, grab 800-grit sandpaper and sand in a side-to-side motion, applying even pressure, periodically wetting the sandpaper with soapy water or Quick Detailer spray. Be sure to keep the surface wet at all times to prevent heat burns on the plastic.
4. To remove the coarse scratches from the previous step, continue the sanding process with a finer 1,200-grit, then to a finer 2,000-grit, and finally to a 2,500-grit sandpaper to remove scratches left by the previous grit.
5. Apply a plastic polish or swirl removal compound after sanding with the 2,500-grit sandpaper and buff or wipe off with a shop towel. We found the Mothers Polish Ball helped speed up the polishing process.
6. Clean the lens with a plastic lens cleaner or soap and water to remove any polish residue before applying wax or protectant to the headlight lens.