Have done a few bits to the Forester recently. First up, the headlights had gone cloudy - so I bought an Autoglym headlight restoration kit, which was dead easy to use. The process didn't take long, and the results were remarkable. I also sealed the freshly polished lenses with C.Quartz DLUX afterwards, which should prevent against oxidation and UV damage for a while (as that protective coating is what I'd effectively ground away). Does feel very odd sanding down plastic lenses...
Before:
First passes:
During polishing:
After:
Here's the other headlamp, prior to any work. It's the more damaged of the two:
After:
A vast improvement, in any case, and it has made a difference to the light output.
Flashed over the rest of it, just to bring it up to scratch.