By Kacky from Wrightsville Beach, NC
The yellowing you see is oxidation from sun exposure. There are degrees of oxidation, and the degree to which it can be removed depends on how much work you are willing to do. The only way to completely restore a yellowed headlight is to remove the oxidation, exposing new live plastic.
If there is extensive micro cracking deep into the plastic, the headlight may not be restorable, but surface oxidation and micro-cracking can be successfully removed. The trick is to remove just enough plastic to make the lenses clear again and then protect them from future damage.
Yes, the creams and pastes will work to some extent in making the lens look clearer temporarily, but this is mostly a result of filling in the micro pitting / cracking on the damaged lens, and doesn't last. They are a quick cheap temp fix at best. The kits such as the ones made by Permatex, Meguires and Turtle Wax do work really well, but you have to follow the instructions exactly, or you will damage the headlight, as some here apparently have. One trick I have found that helps is to if at all possible, remove the headlight from the vehicle, as it makes it a lot easier to do a proper job.
Now to the kits. They are all basically the same in that they have 1) Abrasive sheets, pads, or sandpaper, usually in grits of 1000, 1500, 2000, 2500, and 3000. 2) Some sort of polishing fluid or paste. The trick with the abrasives is to start with the FINEST one that will remove the oxidation (1000 grit is the coarsest I'll start with) and to keep the headlight and the sandpaper pad very wet. Soak the paper for a few minutes in water, and keep a spray bottle of water handy to keep the headlight and paper wet.
Spray the headlight, the, sand back and forth in one direction with the 1000 grit (keep it wet) until most of the oxidation is off and you have a smooth surface. Then wipe the residue off with a wet terry cloth towel, and switch to 1500 grit, sanding 90 degrees to the direction you did with the 1000 grit. (Again keeping everything very wet.) Wipe it off again and now go to the 2000 grit, 90 degrees from the direction of the 1500 grit. lastly, wipe it down one more time and repeat with the 2500 or 3000 grit.
Now wipe off all the sanding residue, take a clean terry cloth rag and use the polishing paste or liquid liberally, and polish in a circular motion, until the lens becomes clear and shiny. Step back and admire your hard work.
The Turtle wax restoration kit comes with a lens sealing wipe, that you apply in one direction, then let cure for 24 hours which will prevent re-oxidation. If you aren't using their kit, you can apply Plastix polish or one of the aforementioned cremes with UV protectant. Then, whenever you wash the car, take a few minutes to touch up the headlights, and you shouldn't have to do the heavy duty cleaning/restoration again.
We tried a product from the auto store, kinda worked but not all the way clear. I suggest you go with Anna Parker.
For a small fee a body shop will polish the lens of your headlights and they will look like new. Any dust or film that is on the inside will be removed also.
3M makes a product to dress up the faded lens. It is available in Auto stores. You will sand the lens using products that come in the kit. You sand using an electric drill. If you go to google.com and type in "3M products to restore headlight lens" some sites will come up so you can see the product and read the step by step directions.
Add your voice to the conversation. Click here to answer this question.