I just replaced hazy headlight lens covers on a late 90's Me

I just replaced hazy headlight lens covers on a late 90's Mercedes. anybody know why they get hazy and how ..
I'd stop that from happening again? My 1st guess could be it is from the sun, but the fog light covers have the same haze. Is it just from time, or substandard plastic instead of the common glass?

the use of plastic is the problem. I have heard polishing them with toothpaste will clear them up as toothpast has a good grit to it.

As you suggested, it's a mix of the things you mentioned. The plastics used, condensation, and UV rays. it's unavoidable.

Some times yellowish is old wax. So attempt hot dish washing soap and water with a nylon clean pad thing you use at the sink use round motion. The car guys sometime use toothpaste to polish out the lens. In cases where the cracking is inside the lens replace the Head light assembly. The surface may be sanded and repolished and clear spray also helps. After Ten years there must be something that make you go to the dealership to purchase a new car. Besides Air Bags only Last Ten Years.

Road debris, like sand and wind and small rocks, they all chip away also as the sun. This is another way instead of replacing, go to walmart and they will have an attachment you put on the end of a drill, it has a matter you apply to your <span title="headlights/taillights/foglights">headlights/taillights/foglight. that will really brighten them back up. Its only 20 bucks, where as some new headlights are.rather costly. A good way to stop it, get some headlight covers from your local auto parts store or ebay. Its just a plastic shield, and at night you may be able to just unvelcro it or slide it out, and your headlights look and work just good. Good luck, hope this helps a bit

As Phil mentioned, it's the poor plastic used by MB for light covers in this era. The newer models use a better material that does not haze caused by the UV light from the sun.

It isn't a increase of wax or anything that may be scrubbed off, so do not attempt removing it.

Keep it in the garage when you may be able to,protect them believe it or not,with a sunscreen.Aluminum polish will bring them back to new.

The haze is from a thin plastic covering they put on the lenses throughout manufacturing to decrease stone chipping. Unfortunately, this plastic ages and yellows after some years of UV light. There are many fix kits available, but the best one is available from any GM dealership. Their kits are made by 3M and are the only ones accepted for GM warranty, so you know it works.

Go to one of the real Mercedes forums benzworldthe or mbworldthe or mercedesforum.com or mercedesshop.com and you will find dozens of postings on this subject and good explanations on how to polish lenses.