Actually, I've tried an emory board, fine sandpaper, pencil lead, hacksaw blade, even a slip of paper under the string and still on two of my three guitars I still get the "PING!" of a stuck string and it's only the G. Presumably because its windings are fine enough to bite into the plastic. I'm ready for a neck reset on one and when I have that done I'm going to replace the nut with bone to see if that helps.--John