As mentioned in the Essex basses thread, and quoted from Dan Erlewine's fret levelling article in BP:
"To begin this job, remove the strings and wax off the fingerboard (but not the frets) with
standard floor paste wax, and run a bead of water-thin (No. 10) superglue along each fret."
Here in Australia it's often hard to find 'common' or 'standard' supplies as listed in US articles
Using my SSD NS-4 as a guinea pig, I've found you can use regular clear sticky tape run beside each fret, with several caveats:
1) You need to be very careful lining the tape up - going over the edge of the fret or missing it is bad.
2) Do NOT do the whole fretboard at once - the fumes are amazingly strong, and as I just found out, the excess glue will stiffen the tape as it dries, making it harder to peel off. I had to go back and very carefully peel back the remnants with a sharp blade.
3) You will probably still get the odd drop of glue on the fretboard if you're not careful. Blot the worst of it, scrape off the remainder when dry.
4) Be careful not to pull the finish off the edge of the neck - I folded the ends of the tape over so both sides were non-sticky, and it seemed to work ok.
It's still easier than finding wax and removing it when done, IMO. The frets are rock solid now, just going to let the glue cure overnight before I start levelling.
