On Volvos, we've tried a lot of techniques over the years, the most common was wet-sanding and buffing the headlight until it cleared up. This technique is okay but not the quality that I want.

We've decided to remove the headlights, wet-sand with 600 grit, hose off the entire assembly, then use urethane clearcoat. Here are the results.

 

I'm very impressed. I typically polish my headlights with compound and a lamb's wool bonnet. They look new, but they oxidize again after about a year. I saw someone using floor wax, but they turn yellow pretty quick. You're solution looks like it will last a really long time.

 

I've studied the issue extensively before we did this. Essentially, the original headlights have a type of UV coating that resists the degradation that we experience on plastic lenses. The UV coating breaks down and you end up with the plastic exposed the elements. It breaks down and the outer layer begins to absorb the dirt.

The finish that I am using is the same that gets sprayed on the vehicle after the basecoat is applied. It is an automotive urethane clear and it is very hard when cured. I just couldn't justify us spending 90 minutes or more trying to buff out a set of headlights only to have mediocre results.

The time to remove the bumper, headlights and reinstall is about an hour. The time to prep a pair of headlights is about 30 minutes, wet sand and rinse. Add another 30 minutes for finish and those are the results. I would imagine that this finish will last the life of the vehicle.

So, instead of 90 minutes for mediocre results, we spend two hours and get these results. I would estimate that each clearcoat job costs us $8.00 worth of materials.