Cannot smelt a Copper Still

[Wargasm 1,928]

 

So I decided I don't want this clunky ugly thing sitting on my deed, so I heated it up to smelt it back down into copper.  When I activate a smelting pot, click the "smelt" option, I get this:

 

[15:17:34] You'd want to empty the still first.

 

As you can see the still is empty, but the game considers it not to be empty because of the sub-compartments inside.