Scraper.
I made mine out of a worn out file. I ground the flat side smooth, and also the edge, into a skate type edge. I ground the tip of the file to match the octagonal bottom three flats, but polished them smooth so they would not cut. Then carefully pull the vertical file along the edges removing wood slowly and evenly. Finish with a file wrapped with abrasive paper. Ten thou....less than one hour job.