I'd recommend the 3M Headlight Restoration Kit if you're just going to perform this on a single set of headlights. If you're going to restore a couple of headlights, then go ahead and purchase Wet/Dry sandpaper grits: 500, 800, 1000, 1500, 2000, and Meguiar's unigrit3000 (if you want a unique clarity). 5 minutes with each grit using a side to side motion allowing the sandpaper to do the work, which means, don't apply too much pressure. Be firm, but do not press hard.

Just remember the four step process:

1. Clean
2. Sand
3. Polish/Buff
4. Seal to endure any further oxidation