I run it through my drum sander on a strip of 1/2" thick styrofoam insulation, nodes down, so it don't get any dips where the noded are. I take off about .025 at a time until it's flat.
I know everyone doesn't have a drum sander, but if you make lots of bows harbor freight sells a model for about $475. I got one over a year ago and have been using it everyday (except Sat and Sun) with no problems.
-Mike