Don't know any of this from personal experience , but i've done quit alot of googling on the subject (as I'm getting ready to try and fix my yellowed lenses as well).

The toothepaste thing supposedly works because of the flouride in the toothpaste. Although the way I read it (on several sources) was to basically coat them with it, let it sit over night, and then wa**** off. I've also seen several sight this as method that works, but only temporarily.... in other words the yellowing / hazing comes back.

Walmart sells a kit for this (which includes a clear coat to help keep it from reoccurring) for about $20. and while everythign in the kit can be bought seperately, that's the route i'm going. I'll post before andafters and let ya know how it works out.

******EDIT***
Ok, finally got around to making a tri to wally world today, as well as several auto places and dropped a knot on car crap lol
anywho, the product from walmart is called "crystal clear", comes in a foil pouch and basically consists of :
1000 grit sandpaper
2500 grit sandpaper
a plastic polish
clear coat
cost: $20.-
you wet sad the surface to remove damage (yellowing or grey stuff that makes it foggy) then use the liquid polish to resurface the plastic and make it smooth again. Then a clear coat , applied with a spplied cloth, twice.
Mine were REALLY bad, so it took about 2 hours ... from having to sand so many times (rather than just once) & my just being slow about it...but they look awesome!
whatever you use to clear up your lights i would defnitely recommend using some type of clear coat to seal it all or you'll end up doing it again, and again...

 

Ok I just bought a 98 Camaro and I have the grose looking foggy headlights and want to clean them but... I just can't figure out how to get the damn things off lol (feel kinda dumb asking butI really don't know)can anyone tell me how to get the covers off???

 

So do you have covers on top of the stock headlights?? Just trying to make sure what i'm reading is correct.

Second, feel free to ask as many questions as you want, there are a lot of very knowledgeable people here and a lot that are just learning, so no question is 'too stupid', and most people here are cool about giving you the best answer pretty quick, so no worries, enjoy the site.

 

yah it's the 98 style headlights with the clear covers... only mine are foggy and dirty!!!

 

Yeah I would try the toothpaste method....it worked for me, but like the JJ_77 said, it is not permanent....Invest in the kit I would say and that should at least make it look better. Clear headlights look better on a black car more than foggy and yellow for sure lol.

 

Did use a toothpaste on my headlight before. It works. I read it from other forums how to handle yellowish headlights. A simple process with great output.

 

Hahaha.

Toothpaste...

I use to usetoothpaste on my model cars that were molded in color. After a little buffing with McCleans toothpaste (yes, Im THAT old), I had a nice, shiny surface that looked like it was painted.

Iwas under thebelief that toothpaste is a mild abrasive. McCleans was more abrasive than the others, but still very mild, less than even jeweler's rouge.

 

I believe that Meguires makes a plastic cleaner/wax that will do the trick.

 

I recently fixed my cracked/fogged headlights by using 1500 grit sandpaper and tootpaste. The toothpaste acts as the equivalent of about 2000 grit + sandpaper. Meguires does make a plastic polish called "PlastX," I've used the Meguire's prouct, but when it comes to polishing I found that Mother's "Plastic Polish" and a Powerball Mini makes a great combination. There is also a product called "Novus 3-Step Plastic Polishing Kit" that I have yet to try.

Here is a link of a guy on LS1tech that used the Novus kit. http://www.ls1tech.com/forums/showthread.php?t=157192

No matter what, if your composite headlights have seen better days, you'll want to follow the process of using a fine abrasive, and then an even finer abrasive, followed by a polish to shine and seal.

 

The kit from Wal-Mart does works great if you don't have access to a buffer, and even if you do it is an all in one kit and eaiser. Toothpaste works if they are not to bad. I tired many different things but only some sanding was going to get it to clear up. Go to myheadlight.com, that is the web site for the stuff from Wal-Mart, my old Camaro is featured under the testimonial section with pictures.