> Apparently adding a spoonful of ammonium nitrate (34-0-0 fertilizer) on
> top of the fire will bring the nastiest bees to heel.  I'm told laughing
> gas is the result!  The bees recover after a short while, and there
> should be no toxic byproducts. (Don't try this at home, kids.)
 
It's true, but be careful, this also produces nitric oxide (NO2), which is
caustic to the lungs.  Be careful not to breathe the smoke yourself.
Especially if the smoke is reddish.
 
I've seen suggestions to use sodium nitrate or urea fertilizer also, if
you don't have ammonium nitrate.
 
-Mike