Can you give some more details on this repair. My lens are destroyed to the point I'm driving around with my brights on. Of course this was before the engine died.

Thanks

 

Sandpaper/Polish systems, seem to be prevalent and often suggested AND I'm sure they might work... for awhile.

My research suggests that there is a UV coating outside the plastic lens. Its the coating is what starts deteriorating/oxidizing. Sanding would certainly remove that coating but would begin a repeating rabbit-hole process as the plastic starts to break down.

It starts as foggy or frosted, then grows more yellow as it progresses. Eventually sanding or replacement might be the only choice. BUT! Before attacking my '01 & '03 Allroad w/ abrasives, I thought I'd try Pittmans ALR (Acrylic Lens Restorer or Alien Liquid Research). After seeing it work, I tend to prefer the latter name

At any rate, you be the judge from this partially done '01 foto. Took only about 10 minutes per headlight w/ a paper towel and NO sanding. Not back to 100% brand new crystal clear, but quite clear, waaay easier and cheaper than replacements. Might be worth a shot BEFORE going the sandpaper route.

 

My lenses on my 2001 A6 avant were pretty messed up when I got the car so I took it in for a pro restoration and it was wonderful. The hazing started coming back after the pro cleaning so I bought the turtle wax headlight restore kit and used that and worked wonderful for me. To keep it up I use the turtle wax express lens cleaner every other month or so and then i apply a coat of meguires ultimate wax and my headlights look amazing always....if they are really really bad a pro cleaning would be a good option then it's all about maintenance.

 

I believe the sanding / polish method is definitely the way to go when restoring your headlights (versus replacement). The reason it gets cloudy in a few months is because the UV protectant layer has been removed during the restoration process. I've found that the Griot's headlight restoration kit is the best as it provides you with an excellent UV protectant spray.

Just my two cents. Good luck!!

 

This foggy look is caused by UV damage to the plastic. The foggy part is the surface of the plastic. Try what Budhani said. Use a super high grit sand paper or even a wet stone used for autobody paint repair. Then finish up with a polish system after you get the "dead" plastic off. Mileage has no bearing on this its all about the age and how much time your car spends in the direct sun.

 

You need to be more drastic with your headlights!!!

Sand them with a fine grade wet and dry paper and plenty of water. Then polish them with rubbing compound using a buffing pad on an electric drill. Do this with finer and finer compounds. Finally with T Cut or something similar. then polish.

Hey presto! brand new lights for the price of sand paper and polish!