Well, my vote would be to leave them alone unless they're really large and out in the open all the time...which they probably won't be. Bristleworms are considered to be a fairly beneficial part of your CUC, especially in FOWLR setups, and they usually don't get in the way. You can remove any big ones you come across by hand, but the small ones should be left alone to clean up after the fish.
If you really want to get rid of them, I know a few wrasses eat bristle worms. Usually only the small ones, though.....you'll still need to remove the big ones by hand. Some triggerfish have also been known to chow down on bristle worms as well.