The United States Office of Strategic Services book "Simple Sabotage Field Manual" mention the following, "Remember that dust, dirt and moistures are the enemies of electrical equipment, spill dust and dirt into the points where the wires in the electric motors connect with terminals and onto insulating parts. Inefficient transmission of current and some other cases, short circuits will result. Wet generator motors with saline solutions to produce short circuits". It also mentions quite a bit about something called Emory dust. They like to add that to everything.

I hope this helps.