First go to PoK (I think this is a PoP recipe too, heard it only works here) and go see Caden Zharik at -350 +750. He sells fishing grubs for a few copper. Buy lots. Next run down to the planar brew barrel at +10 +200. Nearby is a barbarian named Perago Crotal. He sells flasks of water for just over 2 silver each. Buy lots of that, too.

Finally, kick smithing temper folks off the brew barrel and get to work. One fishing grub and one flask of water make a Fetid Esscense, which can be sold for just under the cost of a flask of water.