Shank(s) Stuck in Glycol Block

[skidmark]

I'm trying to dismantle my four-faucet Glastender T-tower to refinish the brass, but I've hit a snag. The shanks are stuck in the aluminum glycol cooling block. They appear to be plated brass, so it may be dissimilar metal corrosion. Dunno.

Any experience? Random thoughts?

Thanks for the help!