I'm getting ready to work on my headlights that look terrible. From those of you who have restored your milky headlights, what is the best product to use; Mothers plastic polish or meguiars plastx polish?

 

Either one will work fine. Try using the Powerball mini with whatever one you choose.

 

Meguiars mag and aluminum polish did wonders for my headlights, best trick in the book.

 

Mag polish can generally be helpful for an initial "cut," but you might find plastic polish will work fine on its own.

For Mothers Plastic Polish vs. the PlastX, the Mothers seems to have more bite than the Meguiar's... not that one's better than the other, but knowing that might be helpful.

If you do use mag polish, unless it's a very fine-cut polish, you'll want to use a plastic polish afterwards for optimum clarity.

As Juztang recommended, the PowerBall Mini (or a regular PowerBall if you already have one) will make the job go real fast. The small size of the Mini and its extension make it very controllable. Mask the surrounding areas with low-tack painter's tape and you'll have a little more freedom. It'll probably take longer to mask than it will to polish... it goes pretty quick.

This is all assuming you're dealing with surface clarity issues and not some problem with the lense itself, or the surface inside, but you'll have some improvement that's for sure.