Headlight polish
 

The lenses were horrible. Before and after shot below.

A few minutes with a Mothers NuLensTM Headlight Renewal Kit and they're much clearer. In spite of using the most aggressive parts of the kit starting with 800 grit wet followed with 1500 grit wet and finally 3000 grit wet before buffing with the compound there are still defects though. You can see the cloudy appearance along the bottom of the lower picture. Seems like the cloudiness is actually buried inside the lens but it is less obvious when wet.

Much better night vision now. Now I need to fix the auto level linkage on the rear as the lights are pointed at the sky.

http://img.photobucket.com/albums/v1...ps3ictlraa.png

Are you sure that you sanded enough? Do it again and concentrate a little more in that area. Then compound polish with vehicle buffer.

Headlamp Guards
 

If I may add my 2 cents... after doing the cleaning and buffing thing on my other vehicles too often, I decided to try another path, headlamp guards. The first image below shows some yellowing after 10 years use, during which all I did was wash the headlights during my normal wash.
The 2nd image shows the lens after I replaced the 10 year old lamp guards with new ones. Incidentally, the lens had minimal degradation after I removed the 10 year old lens guard.

After doing the cleaning and polishing, you need to protect the "naked" lenses or they will be like before after a few month. Many choices for protection.
I have 3M clear film on the X5. Ceramic Coating the Odyssey van and my M5.

When I said 'a few minutes', it was a vast understatement. I sanded the pi$$ out of it. These lights had been done a few years ago by the PO and he said he was nervous he'd sand right through the lens. I'll do it again in the spring once the road shite is cleared away.

According to the Mothers bumf, the polish has protection built in. That said, a clear UV film can't hurt. The lamps on my E60 are still perfect and have never been polished.