Any highly-flammable liquid fuel with which a resourceful Boy Scout might augment the construction of his campfire, i.e. gasoline, kerosene, ethanol, naphtha, etc.
Scout: "I try and try but I just can't get this tinder to light! I think it's too wet."
Adult Leader: "Fear not, for I come bearing Scout water and good tidings. Now go find me a left-handed smoke shifter."
Scout: "A what?"