Is there any decent product that will clean yellowed, dingy headlight lenses?
Thanks.
There are several products that will restore your yellowing plastic covers, go to any major auto parts chain and you’ll find one that is suitable.
If you have an older car, I also recommend you upgrade the lamps as well. I installed the Sylvania Silverlight lamps and the difference is night and day. I’ve had them for six months with no problems but supposedly the lamps burnt out early. They are about double the cost of even haligon lamps. But you see the road so much better. Even if they fail early I’m going to replace with these lamps.
I used the Meguiar’s PlastX on some trucks at work. It has a light abrasive that’s supposed to remove the oxidized plastic. Apparently I wasn’t persistent enough to get all of the bad plastic off; They got dull again pretty quickly. Since you only have one or two sets of lights to do, maybe you won’t have to spread the elbow grease as thin as I did. 
For extreme cases, there are kits that use different grits of sandpaper and a drill. For mild cases, any of several mild abrasive products, a rag, and some patience will help a lot.
They will never look like new again, but you can improve them significantly.
Once you have taken the top layer of plastic off, the rough raw surface will oxidize more quickly, so it is important to keep a sealer like Armorall on them to delay oxidation.
Don’t you just love the advances of the auto manufacturers who put expensive plastic covers where we used to have sealed beam lamps that cost little, easy to instal and adjust and never yellowed. They call it progress.
My truck (2000 Ford Explorer) came with GLASS lenses. Others of the same model had plastic. My neighbor’s Toyota Sienna minivan also has glass. After seeing the effect of plastic lenses on other cars, I will not buy one with plastic lenses.
The best idea is to buy after market lens on ebay. I replaced both on my 99 Camry and it made the car look new. Plus it’s a safety issue. You lose 50% of you light as it is diffused through the clouded lens.
3M makes such a kit. You use an electric drill to spin the various abrasive discs. I have been very pleased with the results, except a couple layers of masking tape were not enough to prevent paint damage where I let the drill drift too close to the bodywork. Next time I will tape on something tougher, like pieces of plastic milk bottle, to protect areas adjacent to the lenses.
How about carmakers using glass sealed beam lights underneath a plastic cover? The plastic cover will give a sleek look and some increase in MPG. If the cover deteriorates, the owner can polish it, replace it, or remove it to get full illumination again.
I was told at buy a guy at a junk yard to put a drop or 2 of anti-freeze on a rag n rub it on the lens. Ive never tried it. let me know if you do. Thanks
I’ve had excellent results using regular polishing compound with a sponge type pad mounted on a regular hand drill. Use plenty of water along with the polishing compound.
Try the cleaning/polishing option. If it doesn’t work, or doesn’t last long, replace them. I found them at Rockauto for about $90 each for an '01 Forester.