Headlights become dirty over time from debris such as dirt, mud, pollen, grass, tar and insects accumulating on lens surfaces when a vehicle is parked or in motion. Additionally, debris baked onto headlight lens surfaces by heat from the headlight elements and fine scratches caused by debris or rocks can turn headlights yellow or hazy. This can block or alter the direction of light making it difficult for the driver to see at night. To maintain the appearance and efficiency of the headlights, clean and restore them at least once a month.
Fill a bucket with hot water and enough mild detergent to make the water sudsy.
Wash the headlights with the soapy water and a soft, lint-free microfiber cloth to remove surface debris.
Scrub away stains or hardened debris with a nonabrasive scrubbing pad or soft-bristled, nylon brush. If dealing with tough stains or debris, apply a slightly abrasive paste---baking soda paste made from a few drops of water mixed with a cup of baking soda or toothpaste---to the area and scrub across the surface again with your pad or brush using a side-to-side or circular motion.
Rinse the headlights thoroughly with water from a hose or empty the cleaning bucket, refill with fresh water and pour the water over each headlight.
Dry the headlights completely with a soft, dry cloth.
Apply a glass or plastic cleaner to the lenses with a soft, dry cloth.
If a slightly abrasive paste doesn't remove a stain or debris, dampen a melamine resin foam eraser and gently rub it across the dirty area to dislodge the staining material. If a headlight lens remains yellow or hazy after cleaning, apply a headlight polish to the lenses and buff with a buffer. If the polish doesn't work, use products from a headlight restoration kit to remove stains or clear up haze. To protect the lenses and reduce the amount of cleaning required in the future, apply a headlight protectant product onto the lenses with a cloth after cleaning.
Always test any abrasive cleaner--baking soda, toothpaste or melamine resin foam eraser--on a small, inconspicuous area of the lens before use as some lens materials scratch more easily than others.