"Paul Keinanen" wrote in message
...
Are the coke cans made of iron ?
Anyway, there would have to be a metal to metal contact that has
oxidised in order to have this kind of junction problem, so I do not
understand how thrown away cans could normally create such junctions.

Cans are made of aluminum now, but 30 years ago they were steel. Back then
it took some hand strength to crush a can, now a little girl can do it.