I was thinking of just making each one completely random, and would call a common event like this:
VarA: Random # between 1-4
If VarA = 1, do the following: (25% chance the pot contains an item)
VarB: Random # between 1-5 (or however many types of rewards, 5 in this case)
If VarB = 1 {
10 Gold
} If VarB = 2 {
Potion
...etc.
That way you can choose to search a pot, and if it contains something: fine. Otherwise, no big loss.
On the flipside, the chests that are currently implemented will always contain the same items/gold. Pots simply serve as another means of getting extra gold if you need it.