I tried the glue on envelopes and I tried sugar cubes and have seen both of them emit a faint blue glow. And I assure you I was not standing in a vacuum chamber when I tried it. Just try it yourself in a dark room. It actually doesn't have to be exceptionally dark, it's pretty visible.

And there are of course also videos showing the effect, here with duck tape outside a vacuum chamber. [1]

[1] https://youtube.com/watch?v=54R6q2_-4Yo