They were last used for soda many years ago. I bartend at an old restaurant and they were sitting in the back room for a looong time until I rescued them.
I've got a 10 gallon corney on ebay right now if anyone is interested. I actually have 4, but want to see how this one goes before I list the others. Check it out.
http://pages.ebay.com/link/?nav=item.view&id=261224978223