Flasks of oil are an essential old school dungeoneering tool, along with the 50' ropes and 10' poles. Light them and throw them at enemies, or pour them onto the ground to make a simple DIY trap, tossing a torch at the right moment. Fire is a great equalizer when you have 6 hp and you're facing dozens of organized enemies. (Roger Raupp from "Don't drink this cocktail -- throw it!" by Robert Plamondon, Dragon 40, August 1980)
The article refers to "molotov cocktails" throughout, but it seems like a different name would be used in a world with no historical Soviet Union. Also note the cleric with a cross on his tunic, a common motif in AD&D art.











