Poor clarity on headlamps can result in poor performance and MOT failure. Over time UV light can damage the plastic clear coat on light lenses and give and opaque or peeled finish. This can be improved or in most cases completely removed to give a clear lens that will not only look better but will perform better.
Damaged and poor surface can be corrected by using very fine grade wet and dry sand paper. Too rough a grade will result in scratching that can not be removed and cause permanent damage. Therefore care must be taken to gently remove only the damaged dull surface.
Once the area has been improved enough the area is degreased and cleaned in oder to be buffed with a glazing compound to give a good clear smooth finish.
Final option is to either seal the lamp unit with a paint sealer or UV resistant clear coat. Resulting in a clear lens that not only gives the front of the car a much improved facelift but also will give better light performance.