So most of you may already know this as it is a no-brainer, but some might not be aware.
If you run the factory headlights on your quad and dune your bike (rather than being a camp cruiser like some ), chances are your headlights will get dull as hell over time.
It's pretty easy to do and only takes about 10-15 minutes to get them looking way better.
You can polish the lenses using plastic lense polish. I used Maguiare's PastX Clear Plastic Cleaner & Polish. (about 7 bucks).
What a difference!