mikep330 - You are talking about the 3M plastic cleaner correct? If your lenses are lightly hazed or etched that will work fine as well a product from Meguiars, Plastx. I've used both, I like the Meguiars product. If the lenses are pitted or extremely hazed and etched you will have to, at a minimum use something like a Porter Cable buffer. If they are really bad sanding may be your only alternative. Mine started hazing (only the drivers side?) about a year after I had my car. I used the 3M product and elbow grease and it worked fine. After about 6 months the hazing and etching returned. I now use Plastx, the Porter Cable and a "cutting pad" . After 5 minutes the headlights sparkle. I still can see a bit of haze and etch when the headlights are on. I clean mine this way once a month when I wax the car. Also make sure I polish them as well. I also use a detail spray after my weekly wash. These plastic cleaners seem to be a very mild rubbing compound with some polish added.
At one time I thought I could get any headlight looking new, I've done quite a few for fellow Crossfire owners but I have now seen a few that the only route is the sanding method. So it depends on what degree yours are hazed and or etched as to what treatment will work for you.
Good luck