Hi, I need advice on how to repair a crack at the first fret on my Fender Jazz V fretboard. There is also a slight bump near the crack. I would like to sand this down to the neck contour as part of the repair. I use boiled linseed oil on my fretboard so the edges of the crack are probably soaked with that. The crack is about the width of a thin sheet of paper, maybe .002". I don't know how deep it is. Thanks in advance for the help.