Ben is DIY: Headlight restoration.

The X5 is now 9 years old and it spends most of it's time outside in the sun.

The UV rays of the Sun causes damage to lots of parts of the car, basically everything that is exposed from the tires, to the paint to the headlight lenses.  The headlight lenses on our 2001 BMW X5 equipped with the optional bi-xenon (HID) headlights are plastic.  Plastic headlights are notorious for yellowing and getting cloudy when exposed to too much sunlight.  Our X5, though taken care of and cleaned often, is no stranger to this.

Basically the outer layer of the plastic gets damaged, so in order to remove this damage you must remove the outer most layer.  To do this you must use some sort of abrasive, in my case: sandpaper (400, 1000 and 2000 grit wet-sand paper), rubbing compound, plastic cleaner and polish.  I did the sanding by hand and started with the most aggressive grit.  I then followed with several passes of the Porter Cable random orbrital polisher with the different liquid cleaners and compounds.

Looks OK, I think.  However to do the best job I would want to take the headlight off the car and do a much more aggressive sanding.