Is there a cleaner out there that will take off that cloudy film on my headlights?

There is a way, although it's not just a "rub this on there and it'll be new again" deal, you'll need to set aside a good two or so hours to do the job.
I'm going to post pictures later in the week, but I'll post how to do it now since people keep posting about it:

EDIT: I forgot to add that this is for 99-04 model mustangs, but this process should work for any plastic headlamps.

What you need:

"Wet or Dry" sandpaper; 300, 650, and 1200 grits. (most packs come with 4-6 sheets of sandpaper, which should be more than enough for both headlights.)
Cost - about $4 per pack.
Rubber sanding block. I picked up one from Home Depot (I'm sure any hardware store will have them) that has flaps with nails you use to clamp the sandpaper to the block with. Do not get a hard block, you need to be able to contour to the shape of the lense.
Cost - about $4
A sharp blade to cut the sandpaper into strips.
I can't remember the name of the scratch remover, but I'll edit this post after my lunch break with the brand name. You can use any type of plastic scratch remover really, but I just had this stuff around the house so that's what I used.
Cost - about $2
If you don't already have one, a hand held buffer will cut down on polishing time heavily (you don't NEED one, but be ready to buff an inch and a half spot for at least 15 minutes). I'd recomend at least 6", and at maximum 10". You'll need polishing bonnets to go with the polisher; get the ones that look like a thin towel, not the thick wool looking ones. It's better to buy more bonnets than you think you'll need than to run out. It helps that they're relatively inexpensive. :)
Cost - Polisher, $20-$40 depending on where you go. I borrowed one from a buddy of mine that got his for $25. The bonnets cost about $6 for a pack of two, I got two packs and used them all, but you could probibly get away with just using two.
Polishing cloth.
Water. Probibly your shop sink or garden hose will suffice, having acess to a constant stream of water makes a big difference in the end. I also recommend soaking the sandpaper while you're attaching it to the rubber block. (Again, I'll post pictures later.)

Now that you have everything you need you want to do something like this:

1. Detach the headlight housing from the car, turn signal, and headlight bulb. This is very easy to do:
Pop your hood.
Find the two pins that hold each headlight to the car, they're located behind the headlamp, pull straight up to remove them. You'll need these when you're done.
Pull the headlight straight forward (not to the side or another angle) away from the engine and it will jerk out, so don't be afraid to use a little force.
Behind the turn signal you'll see a wire that clips on both the top and bottom of the clip. Be very carefull with the ammount of force you put on the clips because they do break easily.
The headlight bulb has a sleeve that rotates to loosen and slides back. then pull the bulb away from the headlight housing with a little bit of force and it should pop out. Be careful not to break the bulb removing it, it's a pain getting all the shards of glass out of the housing.
2. Clean the headlamps with some soap and warm water.

3. Cut the sandpaper to fit the sanding block. It's easiest to lay the sandpaper down like you're reading a letter, place the block at the top sideways, and cut. Completely submerge the block with the sandpaper attached in some warm water for about a minute and start sanding.

4. Sand the entire lamp where it is effected, you could do the entire lamp, but I left the top alone so I'd have a gauge of how well the process worked. While sanding, be liberal with the water. Sand the entire lamp untill you get a cloudy liquid over the affected area, then rense and repeat two or three times then change in a fresh strip of paper with the same grit. For the best results, do at least two passes with each grit using a new piece of sandpaper after every pass, working your way up gradually to the finer grits. Ex: 300, 300, 650, 650, 1200, 1200. If your headlight looks worse that it was when you started, don't worry. It's going to look cloudy, but evenly cloudy if you did your job right.

5. Now comes the fun part, buffing. I started one headlamp by hand thinking it would be easy, wrong. It takes forever by hand to get any results. I'd put the scratch remover on, spread it around in circles to a small area and it'd look brand new! Then about ten seconds later it'd look the same as it did before applying the scratch remover, not fun at all, but I digress. With the polisher, just put a bit of scratch remover on the buffer (with the bonnet on the buffer of course), and run the buffer over the headlight. Make sure you don't press too hard, because some buffers won't spin if you apply too much pressure. You want to see the pad moving; marking a line on the top part of the bonnet is a good idea so you can watch it spin. Concentrate on one area at a time and make sure you apply the scratch remover evenly. You might not notice a huge difference immediately, but it will look better with time. For the corners next to the rubber bumper, sorry, that has to be done by hand. I couldn't get it with

6. After you finish buffing, take a clean polishing cloth and wipe off any excess scratch remover.

7. Reverse the order of step one. Make sure, when reattaching the headlight bulb to the housing, that you line up the notches before you push the bulb in.

I have used Meguiars Plastic X cleaner on foggy headlights. They weren't really far gone though. Just hazy. It works great for me. I use it when I detail my cars just to clean and polish the plastic from time to time. Later.

I used motor oil I know it sounds weird but it worked alright for me on my 2000

Assuming you're talking exterior oxidation and minor abrasion, use a Mothers PowerBall Mini (or a regular PowerBall) and PowerMetal polish. When you've done the first "cut," wash the ball, let it dry, and finish with Mothers Plastic Polish.

You can do the sandpaper or acid etching route, but you'll probably find the PowerBall to be much easier.

If it's feasible, remove the lens; or mask the surrounding area with light masking tape and it should go fine.

ORIGINAL: shayne

I have used Meguiars Plastic X cleaner on foggy headlights. They weren't really far gone though. Just hazy. It works great for me. I use it when I detail my cars just to clean and polish the plastic from time to time. Later.

I agree the Meguiars Plastic X cleaner works well. Check out this picture.

local://upfiles/35438/90B5F5C281604EAB890721E498FD880E.jpg

there is actually stuff called headilght case cleaner... i think i saw it at target..

I was going to do all that work buying material powerballs and cloths sandpaper, so I just spent 99 for a set of new lights. Im not sure how much they are for the newer gts though I bet they are more because their sealed arent they?

There are also products that you can buy for convert windows. The stuff works really well on plastic its specific for getting that oxidation, and scratches out. Plus its fairly cheap $6-$8 or so.

I was going go the the wetsand and polish route but decided to get new ones instead.

A lot of people suffer in earnest with this problem. Well meaning people would suggest you use what is commonly refered to in todays hi tech world as " the caveman method" to buff and sandthe oxidation off your headlight lens. Thats terrible advice.
Thats not necessary to remove naturally occuring oxidation. However if someone has put a varnish or polyureathane sealer on the lens, Do what you will, it is already damaged beyond restoration.
PITTMAN'S ORIGINAL ONE STEP ALR is a liquid acrylic lens restorer.
It will remove all surface oxidation on plastic or acrylic headlight lens on contact.
It is pure liquid and has no abrasives, it reccommended for restoration of hi tech projector headlight lens.http://ibc34.com/images/KMODNIGHTSKY.jpg (http://www.ibc34.com/CONSUMERREVIEW.html)http://www.ibc34.com/Onestep.htmlThe last thing you want to do with a acrylic or plastic lens is put an abrasive cleaner on it. If you do it will never be the same. You will destroy the protective UV layer and that will cause the lens itself to turn yellow.In addition to that, why spend hours doing something that can be done in seconds? Truly amazing product developed by KMOD ALR (Alien Liquid Research) division. Company also produces VaporWax APC acrylic paint conditioner.

Any bodyshop can take them out, sand the old cheapie clearcoat off it, and reclear it. I did that with both my heads and tails, but added a black base to the clear to smoke them. It's amazing.
http://i42.photobucket.com/albums/e301/seanpaintsflames/SUC50417.jpg

<img src=http://i42.photobucket.com/albums/e301/seanpaintsflames/SUC50417.jpg>

screw it.

ORIGINAL: seanpaintsflames

screw it.

i agree. i bought new off ebay from vendor with 100% pos feedback. its worth every friggin dollar.

I got the plastic cleaner stuff at autozone hanging with the auto bulbs and stuff. Ithink it's only 99 cents. It worked REALLY well on my 96. Also, I've seen people use nail polish remover, but I'd stick with the plastic polish.

All the cheap compunds and clear coats I tried never got the plastic clear. I'll try to find the bottle of stuff I used on mine. It worked really well.

well we just bought new headlights.

easy and simple :D

Easy enough, if you've got the money to spend. [8D]