What to Do When the Headlight Cover Turns Yellow Inside?

[DelLayla]

Solutions for yellowing headlights: 1. Regularly clean the headlights. While driving, the car body is bound to accumulate dirt, and the headlights are no exception. Therefore, use a soft cloth to clean the headlights periodically to prevent dirt from becoming more stubborn over time and harder to remove. 2. Use alkaline water for cleaning, such as soapy water, and clean every three months. After cleaning, remember to polish the headlights with a polishing agent and then apply wax for protection. 3. Polish with carnauba wax: This is also an effective method to address long-term yellowing of the headlight cover, with results that are quite satisfactory compared to the original yellowing. Use specialized carnauba wax to polish the yellowed headlight cover, which can remove minor yellowing and surface marks.

[GraceRose]

My old car's headlight covers also turned yellow before, and I fixed them myself. First, use 800-grit sandpaper with water to sand the yellowed areas—this step requires patience. Keep rinsing while sanding to avoid overheating, just remove the oxidized layer. Then switch to 2000-grit sandpaper for fine polishing. Finally, apply a dedicated headlight restoration solution to form a protective coating. The whole process takes about two hours. Avoid parking in direct sunlight regularly, and clean the covers with neutral detergent to delay oxidation and yellowing. If the covers are already cracked, you’ll need to replace the entire set. Severely aged covers won’t improve much with sanding—poor light transmission affects nighttime driving safety, so be cautious.

[Lincoln]

Last time I dealt with yellowing headlight covers, I discovered a little trick. Mix toothpaste and baking soda into a paste, use an old toothbrush to scrub the yellow spots gently to avoid scratching the surface. For stubborn yellow stains, use alcohol wipes for instant results. Don’t rush to finish the job—apply a layer of car wax to protect against UV rays, otherwise, it’ll turn yellow again in two months. Save money by doing it yourself, or buy a restoration kit for a few dozen bucks, which includes sandpaper and coating agent. Remember to check the seals afterward—leaks causing fogging are even more troublesome. Avoid using corrosive cleaners when washing your car, as they can damage the headlight’s surface coating, making it prone to yellowing.

[TuckerLee]

Yellowing headlight covers are very common, essentially caused by plastic oxidation. First, wash off surface dirt with soapy water, and try kitchen degreaser for stubborn stains. Sanding and polishing is the key step, using sandpaper from coarse to fine grit sequentially. Finally, sealing with glaze is a must, otherwise all efforts are in vain. For those with weak DIY skills, it's recommended to go directly to a modification shop where they can polish it bright in three minutes with professional equipment. Cars frequently parked under trees should be wiped clean of resin regularly, as tree sap corrodes particularly quickly. For daily maintenance, apply a thin layer of Vaseline to the seams of the headlights to slow down aging. If cracks are found in the headlight cover, replace it immediately, otherwise water ingress will render it useless.