Totally hilarious thing I just figured out.
In the underdark in act 1, there is a wizards tower that has a chest on one of the balconies called "chest of the mundane". People are using the item as a bag of holding to carry all the heavy shit you plan on selling (the items in it get changed to nearly weightless spoons, bowls etc.) but I found an even more busted use. You can pick up the barrels of gundpowder/oil/etc in the the chest, and when you throw them they have the effect of the barrel but the weight of the mundane item (so you can throw 40lb barrels of oil/gunpowder a mile like you're donkey kong).