Russ: I have to doubt it. The nests are made of almost pure cellulose, and that just doesn't absorb anything. The only thing I think you might smell would be the sulfur dioxide from the black powder that might be residue on some of the wadding. But nothing else comes to mind. Cellulose has no odor. Its possible that some of the nectar stored in the comb and nest remains and is being burned by the powder charge. That would give off the odor of burned Cinnamon toast, or Burned Sugar- which is always a bitter, and acrid smell.