Oh yea, this hasnt happened to me but a friend told me he accumulated his cans in a trailer and when the trailer was full he'd take the cans in. He was docked once because of the moisture that had collected in the cans froms rain. I take precautions to keep moisture from entering the cans.
Melting aluminum would be a waste of time and resources. And a great way to get less money for it as its now an "unknown"
If its recognizable as cans it will be recycled back to can.
if its recognizable as bar stock/windows siding etc. its a different alloy. And processed in different ways.
I would think it would be a bad idea to spend the money, and energy to melt something only to find out because its unrecognizable it would require special processing and refining anyway. I.E., Why melt it twice?
WHen my oldest two kids were little they would collect cans too, family members would save all their cans if they knew the kids were collecting them, other than getting out and hunting cans they seemed to get more that way...Even though its just can collecting, its a good way to teach them how to get out and make their own little spending money and appreciate the value of a dollar. They seemed to appreciate it more when they have to get out and work for it, ya know what i mean? Good little money making idea for the kids. My youngest daughter, she thinks money grows on trees...lol....she would die if she even thought she had to get out and pick up a can! But thats my fault, now she's 18 still in high school (last year thank the lord) when she wants something i tell her to get a job! (not that she does without, she doesnt) lol...think i'll throw in the idea of picking up cans next time she holds her hand out...