Have you ever left for a long weekend, a business trip, or a vacation and found when you got back that the digital clock was reset?

The likelihood is that you already know there was a power outage when you left, but you are unable to determine when it occurred and how long it lasted.

It is therefore impossible to determine how long the food has been in the refrigerator in the heat before it cooled down again and began to spoil.

Anyone who was required to leave their home was given a great tip by a woman by the name of Sheila Pulanco Russell on her Facebook wall.

The tip will relieve your mind about whether or not the food in your freezer is safe to consume or should be thrown out straight away, while it is also useful to know in case of any extended absence from your home.

A cup, a coin, and some tap water—three common yet useful items that everyone has at home—are the secret ingredient.

In a Facebook post which quickly received hundreds of thousands of reactions and shares, Sheila explains how to proceed. She writes:

“For those of you that are evacuating from the coast, I just heard a great tip. It’s called the one cup tip. You put a cup of water in your freezer. Freeze it solid and then put a quarter on top of it and leave it in your freezer. That way when you come back after you’ve been evacuated you can tell if your food went completely bad and just refroze or if it stayed frozen while you were gone.

If the quarter has fallen to the bottom of the cup that means all the food defrosted and you should throw it out. But if the quarter is either on the top or in the middle of the cup then your food may still be ok. It would also be a great idea to leave this in your freezer all the time and if you lose power for any reason you will have this tip to fall back on.