To clean a headlight using toothpaste, simply dab some toothpaste onto a rag or towel and use it to scrub the surface of the headlight. Use water to rinse it off and wipe it down with a clean rag to ensure that all the toothpaste is gone.
Any type of toothpaste should work for this method. Be sure to use clean towels so you are not adding any dirt or oil that might stick to the headlight. Use enough toothpaste to completely cover the surface of the headlamp, but try to avoid getting any on the painted areas around it. If this occurs, wipe it off quickly. You can also use electrical tape around the edge of the headlight to protect the paint.
Scrub the headlight thoroughly to remove stubborn dirt or dirt that is stuck in scratches. Use clean water to rinse it and a clean towel or rag to wipe all the toothpaste off. Be sure not to leave any residue on the headlamp or it may attract dirt. Applying a thin layer of Turtle Wax or a similar product after it dries may help the headlights stay clean longer. Be sure the water and any waxes applied are totally dry before driving the car.