There is a WEALTH of knowledge and experience in this forum
Do they still sell those little round colored 'smoke bombs' that you could get a fireworks stores?
I never saw saltpeter at a drug store, I should look more closely.
I have leaf blower that should work for non-A/C requiring air supply on a low setting.
is TP tube lying horizontal on its side or does it have to stay vertical while burning?
Something like this may work fine too.
passive trap