To demonstrate it, I made a depression in a small pile of finely ground potassium permanganate, the chemical sold for recharging iron water filters. Then I squeezed the contents of a glycerin enema dispenser into the depression. Potassium permanganate is a powerful oxidizer and reacts with the carbon-hydrogen bonds in glycerin. A few seconds later, the mixture burst violently into flame. It worked every time—no mystery, no doubt about it.