I miiled some white cedar planking a couple of years ago, and then applied linseed oil to them(good or inside face only) without removing all of the access oil. some of the planking now has gummy spots that did not dry ( after a couple years). any ideas on how to take care of this problem? I have tried lacquer thinner,rubbing alcohol,vinegar and sandpaper,but nothing seems to remove it.Thanks for any ideas. Bill