Over time, headlights can become foggy or faded from road salt, soil, bug stains and deterioration of the plastic. In addition, moisture behind the lens can cause a foggy appearance. The issue may appear to be cosmetic. However, foggy or faded headlights reduce visibility by reducing the amount of light that penetrates the lens when the headlights are in use. When headlights are dimmed from dirty headlight lenses, this reduces visibility and increases the chance of an accident.
Headlight lenses used to be made of glass. It was very easy to clean and did not discolor. However, it was difficult to create glass lenses for constantly changing headlight styles. Plastic has replaced glass as the material used for headlight lenses. It is lighter and can be molded in any shape needed for aerodynamics and constantly changing headlight styles. However, plastic is more porous than glass and absorbs soil from the road, stains from bugs and tar making them appear foggy or faded. In addition, exposure to sunlight, as well as the heat from the headlight bulbs, can cause discoloration of the plastic.
Use hot water with soap on a cloth to saturate and scrub the headlight lens. Scrub off all bugs and other soil that has adhered to the lens. If there is tar on the lens, use very hot water to soften and remove the tar. Do not use a scrubbing or abrasive pad because these can form scratches in the plastic that will be difficult to remove. Dry well and apply a coat of wax.
Apply baking soda or pumice to a wet cloth and scrub the headlight lens. This will remove a fine layer of the outer surface of the plastic that may have become discolored from stains or road salt. This method is best for headlights that are cleaned regularly and foggy or faded appearance is not very noticeable.
Use a 600 grit wet sandpaper to remove a deeper layer of the outer surface of the plastic for older headlight lenses that have not been cleaned frequently. Be sure to keep the surface wet while sanding and apply only light pressure. Repeat the process with 1,000 grit sandpaper and finish with 2,000 grit wet sandpaper. It is very important to keep the lens wet while sanding. Follow by buffing with baking soda or pumice. Dry well and apply a coat of wax.
If there is moisture behind the lens, open the hood of the car and remove the screws that hold the headlight lens in place. Take care to avoid touching the bulb. Oils from your hands can cause the light bulb to burst when it is in use and becomes heated. Carefully remove the plastic lens and clean the inside with hot, soapy water. Be sure the headlight lens is completely dry before replacing over the headlight.
Clean the headlights with baking soda or pumice each time the car is washed. This will continuously remove a fine layer of the outer surface of the headlight lens so they will never appear to be foggy, faded or discolored. Apply a coat of wax after cleaning to provide a barrier to prevent bugs, tar and road dirt from being absorbed into the plastic.
