For future reference, in case you ever have something aluminum stuck on something not aluminum and you're REALLY desperate to get it off and have no other options, you could try mercury:
The Amazing Rusting Aluminum
You'd basically scratch up the aluminum and put mercury on the fresh scratches.
Kids, don't try this without qualified adult supervision.
Caveats: It's likely to be slow with the amounts of mercury you'd likely scavenge from thermometers or barometers. Also, it's mercury. Elemental mercury is not the instant death like organic mercury compounds from chemical plants, but it's not particularly nice. I'd recommend good thick disposable gloves and a disposable, non aluminum container to let the reaction happen in. I'd also recommend doing this outside and not hanging about while it happens and the mercury is slowly evaporating into mercury gas. Finally, if you DO ever go this route, you're responsible for proper environmentally conscious clean-up. Seal the gloves, container, and leftover aluminum in an airtight bag and take it to a proper hazardous waste collection site.
Again, this is a solution for the terminally desperate, and you should make sure you cover all appropriate bases before taking it.