When the Les Paul guitar was introduced it was advertised as the first fretted guitar that played like a fretless guitar. The frets on the Les Paul have a low profile, are slightly wider and fit the contour of the neck with more precision than other similar electric guitars. For this reason though, they also need a bit more care because of their low crown and height in relation to the strings. If your Les Paul starts to develop string buzz, it might be time to shave down a few frets.
Hold the guitar in your lap and slide your finger up the strings, one at a time. Listen for a buzz that indicates which fret needs shaving. When you hear a slight buzz stop sliding your finger. The buzz should be coming from the fret directly above the fret where you are holding your finger. Put a piece of masking tape on the neck beside the buzzing fret to identify it.
Loosen the strings on the guitar enough so that the pencil will slide between the strings and the neck of the guitar. Slide the pencil toward the nut of the guitar two frets from the fret that you have identified for shaving. This raises the strings up off the neck just enough for you to get the file under.
Peel off some masking tape and run several layers on either side of the fret to be shaved. Completely tape off the square area between the frets to prevent accidental nicking of the rosewood fingerboard on both sides of the fret.
Place the straightedge centred on top of the fret to be shaved with the 2-inch side down. Rock the straightedge back and forth. Lean down to eye level with the fret as you rock the straightedge, noticing how much the fret needs to be shaved.
Slide the jewellers file under the strings on top of the fret to be shaved. Begin shaving along the fret lengthwise, back and forth until brass filings start to accumulate on the tape.
Remove the file and apply the straightedge to the fret again. Rock it back and forth as you did before. If there is still a rocking motion slide the file back in and file back and forth lengthwise as you did before. File until you see brass shavings. Check with the straightedge. If there is still a rocking motion with the straightedge, continue filing and checking until the straightedge lays flat and level across the frets.
Remove the pencil. Tune the guitar and slide your finger up each fret again to check for buzzing. Repeat the above process if you find additional frets that need shaving.
Run your left hand down the sides of the guitar neck lengthwise, if you feel rough ends on some of the frets shave them down as well by gently filing off sharp ends.
Use care when shaving down frets; don't take too much off. Only make a few strokes with the file before checking with the straightedge.