Our VW Jetta is almost 10 years old, and thanks to it being a diesel, it is really just starting its engine life.
Unfortunately, the headlights didn't get the memo!
So, I tried a lens restorer by Turtle Wax. It certainly takes a little elbow grease since you are essentially sanding the lens 4 times.
First, you use the clarifying compound, and depending on your damage (just yellowing?) you only have to do that step. With ours, the surface is actually gritty due to sand and weather hitting it, so we had to proceed to the sanding phases.
Although it is not perfect, it has made an incredible difference in the look of the headlights.
Total work time: 25 minutes
Cost: $12 CDN