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&#x27;t have to be exceptionally dark, it&#x27;s pretty visible.<p>And there are of course also videos showing the effect, here with duck tape outside a vacuum chamber. [1]<p>[1] <a href="https:&#x2F;&#x2F;youtube.com&#x2F;watch?v=54R6q2_-4Yo" rel="nofollow">https:&#x2F;&#x2F;youtube.com&#x2F;watch?v=54R6q2_-4Yo</a>