Car headlights are made of polycarbonate plastic, making them more durable, but this also leads to a potential hazard—oxidation buildup. When the sun shines on the headlights, it expands the pores of the polycarbonate plastic on the headlight surface, accelerating oxidation and yellowing inside the headlights, and also causing dirt and debris to adhere to the outer surface of the headlights. Below, we'll teach you how to prevent headlights from turning yellow and ensure headlight clarity. 1. Use a soft cloth to wipe away dirt, debris, and fragments from the headlight surface. 2. Clean the headlights with soap and water every three months to prevent the buildup of dirt and debris and avoid yellowing. 3. Polish the headlights after cleaning. Use a chemically synthesized polishing agent to wipe the headlights and wax them according to the procedure. 4. When not using the car, park it in a garage or shaded area. This will help reduce UV exposure to the headlights, which causes oxidation of the polycarbonate.