Mates,
Many guitars have a dedicated slot to fit the nut (as opposed t o it simply sitting at the end of the fretboard). I would like to buy files for this in standard nut width sizes, maybe even specifically designed for guitar. Unfortunately, searches for "nut slot files" or the like only...
For those of you who have expressed interest in attempting a refret, this site lays out the steps nicely.
Refretting Electric Guitars | How To Remove Frets, Clean Slots, Choose Fret Wire, Seat Frets Properly, Level and Polish New Frets