I was making Bone Temper. 1 Goblin Bones + 1 Water. When I was finished I had 4 of these in my inventory. Seems like the fails for the temper return this item. Not sure, but.. I am 100% sure I did not have them in inventory before I started making the tempers.
Best guess is vendor loot. PoP heralded the begining of droped items that served no purposes at all except as money.. which does make a good ammount of sence as a stack of these things weighs a whole lot less than the 300 or so pp that the stack is worth. (Each vial being about 17pp each if I recall correctly)