Common black powder such as old women use to blow out the copper flues.
R. Austin Freeman - As a Thief in the Night (1928)
Apparently women sometimes did this when the washday copper was heated by a coal fire and sooty flues were a problem to be resolved without the expense of a sweep.
The intrepid ladies went out and bought little packets of gunpowder, threw a packet into the fire under the copper, slammed the door and – whoomph. The gunpowder blew a thick black cloud of soot out of the flue. Job done.
Different times, different ways.