Plastic headlights are manufactured with an outer ultraviolet (UV) protection coating. Over time, this coating degrades from exposure to the elements, causing fading, yellowing, oxidation and general deterioration. Restoration of the headlight requires you to remove the outer layer of material from the headlight surface. Once you have removed the damaged UV protection layer, you will largely restore the headlights clarity. Following restoration, apply additional UV protection to reduce the impact of UV light on the headlight surface.
Spray the headlight surface with glass cleaner, and wipe away any oils or debris with a towel.
Sand away the UV coating and top surface layer of the headlight. Using 600-grit sandpaper, sand in circular motions to avoid cutting grooves in the headlight surface. Rinse the sandpaper frequently with water to avoid clogging the fine grit. Sand evenly to remove the damaged layer. A dull finish will remain from the abrasive when you have finished sanding.
Polish away the sanding marks with 1,500-grit sandpaper. Sand the surface evenly until you have restored clarity; rinse the sandpaper frequently to keep it from clogging.
Wash and dry the surface of the headlight to remove any remaining particles or dust.
Apply a quality car wax with UV blockers to the surface of the headlight. Allow it to dry, and buff away any residue with a soft cloth.
Clean the headlight to remove oils, insects, tar and road debris.
Purchase a headlight restoration kit online, from an automotive store or at a large supermarket with an automotive section.
Restore the headlight according to the manufacturer's instructions. If using specialised buffing pads, use small motions to avoid over-buffing or damaging the vehicle's paint or trim.
Apply headlight UV protection. If your restoration kit includes UV protection, apply it according to manufacturer instructions. If the kit does not contain a UV protection product, apply a car wax with UV blockers to the headlight. Buff away any remaining residue with a soft cloth.
Restoration kits may require specialised tools, such as an electric drill, as part of the restoration process. Check the requirements prior to purchase. Reapply the UV protection product several times a year for maximum protection.
Sandpaper can scratch trim and paint. For extra protection, cover the vehicle's nearby paint and trim with painter's tape to avoid damaging the surface during headlight restoration.