wrote:
Peter Rathman writes:

When closing the glue tube I squeeze it a bit so some excess glue
coats the threads inside the cap. This gives a good seal without
needing to turn the cap on so hard that it's likely to cause a crack
to start.

Do this with the opening upward to drive out any air (empty volume)
that would allow internal evaporation.

Yes, of course I squeeze it with the opening upward - otherwise the
glue would all end up on the ground. But the tiny air volume inside
the closed tube won't allow for a significant amount of evaporation
before an equilibrium is reached with the vapor pressure of the glue.
If you get a dried out glue tube it's the result of leakage to the
outside, not just evaporation into the small empty space inside the
tube.

Coating a bad cap with glue
won't prevent evaporation.

Nor was it ever implied that it would. If the cap is cracked (i.e.
bad), then the tube will dry out quite quickly. The idea is to seal it
sufficiently but not tighten the cap so hard that it is likely to
crack. I find that a thin glue coating on the threads helps me do this
consistently. I haven't had a problem with a dried out tube of glue in
many years since adopting this technique.