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From the Physics Dept. web site at the University of Augsburg, Germany:

In the course of studying physics, one is officially taught that liquid nitrogen is simply (and mainly) used to cool things down to 77 degrees (K).

But everybody who once has observed students in practical courses "working" with this stuff knows that this is not true.

My intention is now to tell the truth about what is really done with liquid N2 before its remains are taken and used for cooling.

[snip]

1. Freeze a can of shaving cream.
2. Peel the can away from the cream.
3. Put the canless cream into someone's car.
4. Let the oven-like heat from the car's sitting in the sun defrost the shaving cream.

2 cans will fill an entire car.

Thank you, in advance.

(HT to Modnar)