Piles of ash leftover from incinerated trash may be a viable source of hydrogen gas that can be used to generate electricity and power cars, suggests a process pioneered in a research lab.

The trick? Just add water, which reacts with residual metallic aluminum in the ash, explained Aamir Ilyas, a water resource engineer at Lund University in Sweden, who developed the technique.

The aluminum comes from soda cans, milk cartons and other food packaging that gets tossed out with the household waste destined for the incinerator.

Interesting. But how well would that work in places where aluminum cans are separated from trash for recycling? Less well, I assume.