Their are two important variables that work to keep cigars fresh, temperature and humidity. That being said, a cigar humidor is the best place to store your cigars long-term and guarantee their freshness.
An active environment that controls these variables is the only true way to safely protect and age the cigars, however, for a very short period of time, you can keep them in a refrigerator in a plastic bag that within the plastic bag has a moist paper towel within another plastic bag.
A refrigerator, through its cooling process, reduces the humidity in the air and therefore is not a great place to store cigars long-term. You can get away with it for a couple of weeks, but after that, find yourself a good humidor, and one that controls your humidity actively.
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