most likely what has happened is the wood shrunk, and the barbs and ends are sticking out, as metal wont shrink.
couple ways to fix this... get some sandpaper and a block, this will work, most likely will chew through some paper though. If you go the file route, you would just hold it against the side, and go back and forth till they are gone, then you can go back over it with fine 400-800 and above (whatever works for you) sand paper to clean them up and get rid of any file marks. I just use a regular flat file, about 6 inches long.
to keep this from happening again, you can watch the humidity levels in your room, my case the basement. In the winter (ohio) i have to run a humidifier, summer de-humidifier. keep the level normal, and it wont happen.
Dave