On Friday, August 4, 2017 at 9:53:44 PM UTC-4, bob prohaska wrote:
whit3rd wrote:

Penetrating oil to start, and maybe some dry ice (aluminum shrinks in cold more
than steel).

Dry ice never occurred to me, it seems worth thinking about.
I believe it's available at the local grocery store.

Thank you!

bob prohaska

You can improve the heat transfer from the dry ice to the aluminum by making "poor man's liquid nitrogen" which is dry ice in 99% isopropyl alcohol. Be really careful with this stuff, though. It freezes skin on contact. You can also do it with 91% alcohol, but it gets very thick - kind of like honey.. But very, very cold.