Getwetsailing.com

List of Items needed
1.    Good sander and I recommend using about 200 grit to start out. Then working your way to 400 grit.
2.    Long sleeve shirt. (Your arms can get really itchy)
3.    Good dust mask. (You don’t want to breathe in all that fiberglass!)
When you sand your batons you want to sand near the leading edge of the baton. Work your way about 3/4ths of the way down the baton. When you sand, you want to cut that ridge down near the front 1/3 of the baton, what this does is make that baton more flexible, giving the sail a better shape to get the most power out of your sail. Your goal is to get more curve up at the front of the sail, giving you that extra lift. Be careful not to sand too much off, or your batons could end up breaking if not when sailing, then defiantly when moving the sails around.

Wile we are on the subject of batons, you will also want to cut them to length of your sail. I suggest putting the baton in and pushing in on it so it will be the appropriate length when you cut it, then when you tie it in, it will fit nice and snug into the sail.