Well the cans would be recycled anyways, there's a 5 cent deposit on all aluminum cans, the people that don't care and throw them out keep the local homeless population employed collecting cans.
260z, I understand age hardening (also called precipitation hardening) as I understand it the metal is heated up and quenched to reset the structure of the metal, some alloys will age harden at room temperature but others require the material to be raised in temperature (500 degrees or so I believe) for the hardening to occur. As I understand it with aluminum what occurs is the alloying metals form nucleation sites, and the precipitation hardening causes those nucleation sites to form crystalline structures, slightly elevating the temperature depending on the alloy helps the process occur. As I understand it 'in the old days' aluminum rivets for airplanes were made this way. After quenching they were stored in a container full of dry ice to keep the temperature low so the metal stayed soft, after they were actually riveted in place they would age harden at room temperature.
Aluminum's annealing temperature depends on the alloy and it's between 400 and 600 degrees or so. I was able to find information on 7000 series aluminum which age hardens at 160 degrees C
From what little information I can find 3000 and 5000 series aluminum don't respond to precipitation hardening.