1.   Radionuclides are unstable atoms that undergo a spontaneous decaying process that can last from a fraction of a second to billions of years.

2.   You can speed the decaying process by occasionally turning the pile inside out, shifting the undecayed material to the center.

3.   Since it has not been kept on ice for the past two weeks, the decaying process had begun and freezing was no longer an option, Fisher said.

4.   The micro-organisms that help with the decaying process require both carbon and nitrogen to make protein.