The cauldron has been "depopulated". There are very few Goblins or Skeletons left roaming the area, but if your hunting for prawns there is a camp (one of three) that is home to goblins and you can hunt there. Sigh...I miss the "ruff".... but at least it's a bit easier (safer) for low level characters to roam the zone.
I have seen them drop from Aqua Goblin Mariners, and from a rat as well. Dont remember if it was a cauldron rat or a scalded rat. But I am guessing its a rare drop from most of the mobs in the zone except maybe the orcs.