Final word on fretboard cleaning/maintenance

Man, a fretboard should never get to the point where you need to scrape anything off. This would mean that 1. you hardly ever change your strings (the time you should clean your fretboard) or
2. The person playing guitar is playing with very dirty hands. (unpardonable)
Each time you change strings wipe the fretboard down with some turps on a soft cloth. The turps cleans, dries
off and doesn't bother any glue that may have been used to keep the frets in position.