Found this over at the Supra Forums, Headlights are made out of the same material, so it should all work. I don't know if anyone has ever tried this method or not, but I put before and after pics at the bottom of the post. And the site has a step-by-step process.

http://www.mkiv.com/techarticles/headlights/index.html

http://www.mkiv.com/techarticles/hea...recleaning.jpg
http://www.mkiv.com/techarticles/hea...ercleaning.jpg

I was thinking of doing this in a week or two. I have read a lot of posts on different forums about this and this seems to be the most consitant method, not to mention the pics look great. Thanks for the info.

Polishing is simply one way of removing the mold/dirt caused by the condensation inside the housing. One cure for this discoloration is ACETONE, which costs a couple dollars a quart, a few ounces should work just fine. Anyway, with a rag...i used cotton pads, but the cotton has a tendency to shred and meld with the plastic, i was able to remove all the yellow coloring from the lights on my thunderbird, the only part that stayed yellow was the glue holding the clear plastic to the housing, but im not sure that's an issue with S14s.

What a COINCIDENCE! Just did this on Tuesday.  The procedures from the SUPRA forum seam like a hassle, but is probably the most extensive way of cleaning the headlights.  

I used plastic cleaner and then rubbing compound on the OUTSIDE of my headlights.  I later put wax on them to leave a long lating protectant.  It made a pretty drastic difference!  Too bad I did not take any BEFORE/AFTER pics.

I say try cleaning the OUTSIDE first, and if that dont work, then do the INSIDE.