Almost anyone who owns any newer model car with plastic headlight lenses (especially if you live in the South) is well aware that over time the plastic oxidizes from UV exposure. I've seen some lenses that were so yellowed over I don't know how the person could see to drive at night.
When I had my $6600.00 encounter with the concrete divider on the Interstate last winter (due to ice), one of the items that got replaced on my 300M was the right headlight assembly. With a new headlight on one side of the car, it was easy to see that the other light had started oxidizing. This summer, I could actually see the original light getting worse. I did not want the light to reach the point where its performance was going to be compromised, but I didn't want to fork out 400 bucks for a new light, either.
I did a lot of research on the Internet trying to find the "cure" for this problem. What I found was that this oxidation can indeed be polished out using a multistep process involving wet sanding, plastic polish, and wax. Here's the process:
You have to use one of those small palm-held orbital sanders. If you try to do this by hand, you'll probably die of old age before you see any results. Start with 1000 grit (and sand it WET), then go to 1500, then 2000. Make sure to keep the paper and the lens WET and change the paper when it gets loaded with the plastic residue from sanding. Also, you've got to keep the sander moving across the lens at all times. By the time you get through with the 2000 grit paper, the light will be very smooth, but you've got to polish it to get it crystal clear. I used ordinary rubbing compound. Cover the lens thoroughly and then use the orbital sander again over a clean cloth. The final polishing is done with plastic polish. Figure on spending about an hour per headlight to do the job right.
Just keep in mind that this hazing is caused by oxidation from UV rays, so to prevent the hazing from coming back, you need to keep the headlight lenses WAXED with a good quality wax that has a UV sunscreen in it.
As you can see in the pic below, the original headlight now has pretty much the optical clarity of the new one. The only visible difference is in the grey area inside the light, which is somewhat faded in the original light, whereas it's a nice deep charcoal in the new light.
When I had my $6600.00 encounter with the concrete divider on the Interstate last winter (due to ice), one of the items that got replaced on my 300M was the right headlight assembly. With a new headlight on one side of the car, it was easy to see that the other light had started oxidizing. This summer, I could actually see the original light getting worse. I did not want the light to reach the point where its performance was going to be compromised, but I didn't want to fork out 400 bucks for a new light, either.
I did a lot of research on the Internet trying to find the "cure" for this problem. What I found was that this oxidation can indeed be polished out using a multistep process involving wet sanding, plastic polish, and wax. Here's the process:
You have to use one of those small palm-held orbital sanders. If you try to do this by hand, you'll probably die of old age before you see any results. Start with 1000 grit (and sand it WET), then go to 1500, then 2000. Make sure to keep the paper and the lens WET and change the paper when it gets loaded with the plastic residue from sanding. Also, you've got to keep the sander moving across the lens at all times. By the time you get through with the 2000 grit paper, the light will be very smooth, but you've got to polish it to get it crystal clear. I used ordinary rubbing compound. Cover the lens thoroughly and then use the orbital sander again over a clean cloth. The final polishing is done with plastic polish. Figure on spending about an hour per headlight to do the job right.
Just keep in mind that this hazing is caused by oxidation from UV rays, so to prevent the hazing from coming back, you need to keep the headlight lenses WAXED with a good quality wax that has a UV sunscreen in it.
As you can see in the pic below, the original headlight now has pretty much the optical clarity of the new one. The only visible difference is in the grey area inside the light, which is somewhat faded in the original light, whereas it's a nice deep charcoal in the new light.
