I've had some good luck with baking and cleaning up a couple sets of genuine CTR (pre-facelift) headlights. One I did a project retrofit on, the other just to clean up and do a repair on the leveling motors.

Got the chance recently to clean up genuine *facelift* CTR headlights for Thomas C. Genuine CTR headlights have a smoked chrome trim on them, and have projectors. USDM have regular chrome, and no projectors. His headlights originally had water leaking into them, so at some point he opened them to clean out moisture/condensation. Which left some bad streaks on the inside. Then upon sealing he used silicone. Which isn't recommended.

So this post is not really a DIY, but more of a chronicle of the experience in case you want to clean up your own.

Here are the pics of the "before" condition of the headlights:





You can see there quite a bit of silicone:



So Thomas sent those headlights to me, I tried to give them the "spa treatment." My goals were to clean out as much silicone as possible, open each up, clean out the streaks on the inside of the clear lens, buff the outer lenses, reseal them with butyl glue (which is what TheRetrofitSource sells and is really great).

He sent them over in 2 big boxes. I used rubbing compound on the outer lenses first to get a feel for how much of the streaking and defects were on the inside of the lens. I later found that a foam buffing pad is much better than the one in this pic.





Probably the most time consuming thing was removing the silicone. That stuff sticks to the plastic and there are no chemicals that can easily remove it... so it was basically fingernail and pull, fingernail and pull. In this pic some of the silicone has been removed, and you can see the scratches and streaks on the inside of the lens.



Baking the first light! I used two settings:
to open: 220 degrees for 20 minutes
to seal: 270 degrees for 8 minutes
And I placed them on glass coasters. If you put the plastic housings on a metal baking sheet, the plastic will melt!



Opened up:



Chrome trim separated from clear lens:



I spent about 4 hours buffing the first lens. The inside had some kind of "burned in" streaks that wouldn't come out. It was maddening. And the coatings on the outside and inside were coming off as well, which gives sort of a sunburned effect (like when your skin is peeling). I did a bit of wet sanding but wasn't happy with the results.

Then I saw a local on Craig's List selling a nearly new set of OEM facelift headlights in great shape, for very cheap. I drove over and bought them. The clear lenses are identical to the JDM ones.

JDM on top, USDM on bottom:



The only difference on the lens is that the USDM has this DOT stamp at the bottom:



Same spot on the JDM lens:



I buffed the new "donor" USDM lens, which had a bit of hazing on the inside b/c the PO ran HIDs in them (a no-no). Then applied Meguiars Plast-X to inside and outside to seal. Then was ready for the new butyl glue, which comes in a roll that looks like a giant roll of licorice:



Here the new buyl glue has been added over the oem light gray glue:





Minor repairs to cracks (used 3M weather sealant which is a surprisingly good plastic glue):





Then I moved on to the 2nd headlight, which was oddly dusty inside:



New glue added, ready for new donor lens:





Final results!