Fret Dressing
Over time, the frets on your guitar become worn, most often, on some frets more than others. A variety of factors such as string gauge, playing style, and fret material determine where and how quickly your frets become worn.
A fret dressing brings your frets back to level and rounds off the tops again for a like new feel. A fret dressing entails first straightening the neck of the guitar, followed by a leveling using a long straight plane. Once the frets have been planed, a radius block is used to ensure that all frets are the correct radius. Once this has been accomplished, it's time to "crown" the frets.
A rounded diamond file is used to bring the fret back to shape and remove the flat spot on the top of the fret created by leveling. Once all the frets have been crowned, a final fine sand and polish is given to the frets.