Good question !!

In France, the Weather Bureau predicts a cold winter, so we are preparing for that, too.
Forget the Sterno can, it won't heat much.

We are presently testing - on a wide scale - the following method :
- leave the freezed can in the car's trunk ;
- open one window ;
- get out of the car and close the door ;
- throw a Molotov cocktail inside the car ;
- wait for the burned out car to cool down a bit ...
- open the trunk (watch your fingers, it's still hot...) and get the can : it should be thawed ....
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