FlasksOfOil

From ToEE

Approximately one pint of viscous, flammable fluid. Has all the combat potential of greek fire or napalm, but will also fuel a lantern or power a gnomish horseless carriage.

For a single gold piece, this provides an excellent grenade-like effect. Assuming that it's not used in an enclosed environment where the fumes might suffocate a party. Or in a wood-rich environment where a fire could overwhelm the party. Or in a high-oxygen environment where the explosion might take out the party. Or in a narrow location where the fire could block a party's progress. Or...