How to Clean Your Car Headlights 1. The first step is to apply some toothpaste on a dry cloth. 2. Once the toothpaste is on the cloth, begin to rub the headlight cover with it until the grime comes off. 3. Keep rubbing the toothpaste in circular motions until the grime breaks down all the way. After that proceed to rinse with water and wipe down with a wet cloth.