I had the same problem when I had my '98. Some one told me that by using rubbing compound would clear them up. I never tried it, but thought I would pass it along.

 

Yeah, believe it was called Blue Magic.
Very cheap stuff and works GREAT!!
I highly suggest it, much easier then sanding a crapload of times for the same results.
And if you want pick up some epoxy too, incase the buildup is on the inside of the plastic.
If then, you can try taking the whole lense off and clean it up nice n good then epoxy it back on.

 

I have some Blue Magic at home in a spray can. But it is meant for taking out stains in carpet and upholstry (works awesomely!! on evry stain I've tried! Dryed-up cherry Coke, dirt, red clay, oil/grease, grass. I couldn't believe it the first time I tried it.).
SAme stuff or diff? Do you know what the process is?

 

It's very cheap, comes in like a normal polish bottle.
With that flip up spout.
Stuff looks like diarrhea, like a brownish color.
You can find it at Auto Zone or local parts store, just look around.

 

it WILL come back which is why i said to spray a coat of clear on them and it wont come back, and u can wax ur headlights looks really nice.