How can I clean ''foggy'' plastic headlight lenses.

Can go to auto zone they have a scrubbing disc to get the haze off headlights, worked great for mine you just stick them in a cordless drill and buff them.

You can use a very fine steel wool to remove the film. You dont have to press hard to remove it. Pressing hard may result in scratched lenses, however if there is a film, you can remove it useing fine steel wool. There are 4 (i think) grades of steel wool, 0, 00, 000, and 0000. The 0000 is the finest grade of steel wool. Many carpenters use this when wood working to help with the wood finish. It helps polish the stains.