If your Bean boots have an Aqua Stealth sole you don't need to do anything to them. If they are "cleated" soles, then screwing in studs might be your best option, providing you don't want to got the felt route. If you can't afford the $20 for the Simms carbide studs, go to your local hardware store and get some hex head screws. As already mentioned, make sure they won't go all the way through the sole when screwed in. The may not last as long as the Simms, but they are less expensive and can be replaced when worn down.

Dave