Mitchell Abrasives 60-C Round Crocus Polishing Cord, .015" Diameter x 50 Feet

I got this to keep my Gibson Explorer and LP guitar nut slots and bridge saddles notches smooth. If you play practice your guitar a lot the strings will ware small groves in the nut and bridge saddles. The strings will get caught and bind up in the tight grooves ( you'll here a ping) and cause tuning, intonation issues. if you guitar does not stay in tune and does not play or sound like it used to. Smooth your nut slots and saddles. Go easy . your not remove material just smoothing out the grooves