Fret-ends: Filling-in gap with wax?

[perucci]

On the fret-ends of my MIM Jazz, there's a small gap between the bottom of the fret (that sticks into the groove) and the bottom of the wood groove. On most frets it's filled-in with some something that looks like brown wax. Just to be clear, I'm talking about the sides of the fretboard.

Is there something I can use to fill-in those gaps (some sort of wood-repair wax crayon, maybe)? I seem to remember that those little gaps could lead to drying and the fret popping-up, but I read so much here, who knows...

[202dy]

Medium or heavy viscosity super glue is the standard in the field. Apply a dot on each fret end and mist with accelerator. In a minuter or two the cure will be hard enough to work. The procedure is the same as filing fret ends.