Whether you've forgotten about a cigar you were saving or you never learned how to care for one, there are several reasons why your cigar might go stale. The quality of the smoke a cigar produces depends on the moisture within it, and therefore cigars should be handled and stored in a specific way. However, using a few different methods, dry or stale cigars can be returned to their previous quality.
Fold a closed cigar box containing the stale cigar inside of a damp towel. This allows the moisture to seep into the box and re-moisten the cigar. Leave this for several days or until the towel is dry. Feel the cigar; if it still feels dry, repeat the process. If the cigar feels slightly more humid, return it to the cigar box to maintain the humidity.
Take a hot shower with the open cigar box in the bathroom. The steam from the shower will begin to moisten the cigar. However, don't expose it to the high humidity of the steamy bathroom for an extended period of time. When the shower is finished, close the cigar box to contain the remaining humidity in the atmosphere. Leave it for several days to continue to re-hydrate the cigar.
Use a humidor, which can be purchased for as low as $30. These boxes are specially designed to maintain a stable level of humidity, keeping the cigars fresh for a longer period of time. A special solution is used to maintain the particular balance that creates the ideal condition for a cigar, preventing rapid staling.