http://www.ClintsGlass.com - A lot of headlights need to be sanded down until the damaged clear coat is removed completely but not all lenses need to be sanded! Sure you could cover up the cancerous haze with a clear chemical, but if you don't completely remove the yellowing it won't be as glassy!

Watch me completely restore a headlight with out sand paper and see for yourself how all headlights are not created equal.

First I spread compound over the headlight, spray some water to dilute compound. I will use a cheap drill to remove all the scratches and clean the yellow haze off. I will get every part of the lights outer front facing lens. I will use an inexpensive sponge pad on high speed until light is clean and dry. Now I will use a high speed buffer to polish the lights surface with some plastic polish. I will use a buffer on high speed until polish is completely dry on plastic lens. See how the plastic reflects the light? It looks like clear glass!