[JustinID]

Anyone know of any sort of compound that can be used to clean up old hazy plastic headlight lenses? I have an Explorer and I'm just about to the point of replacing the entire assemblies because of how bad it's getting. They're not broken or cracked, just can't get them to clear up with anything like normal glass/plastic cleaners.

[JKnight]

I'm on an email list for jerks like me that have BMW M3s, and one fellow posted this a while back:
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The other thing you should do for sure - repolish the headlights.

They ARE pitted and scratched unless you did this last week..
They seem to scratch very quickly. I'll also be writing the process
up for Roundel also (not original - it's on a number of websites),
basically:

1. Wet sand with 1,000 grit paper. Sand until most of the pits are
gone, or at least reduced a lot.

2. Wet sand with 1,600 grit paper until the 1,000 scratches are gone.

3. Polish with the plastic polish of your choice (Meguiar's Mirror Glaze
#17 Clear Plastic Cleaner on a soft flannel rag works well.)

4. Several coats of your favorite polymer finish (I use Rejex) help
keep them clear.

You can do this with the lights on the car - I'd suggest using
painters blue-masking tape on the surrounding paintwork so if you
slip nothing gets boogered up..

You can repeat 1-3 until you are satisfied... Took me about 45
minutes per headlight. I now give them a quick re-polish with
the Meguiars when I'm waxing the car. Lots easier if you keep
after them.
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He was writing an article for a BMW magazine (Roundel) comparing a lot of aftermarket headlight systems, so he seems to know what he's talking about. I've never done this, be it on a BMW or any other car, so can't attest to its efficacy. I have used Novus products on the plastic of my headlight housing, and it took out some haze:

http://www.ccrane.com/radios/radio-accesso...S110401WSDG0100

Jason