Saving Dry Cigars
One of the most horrific experiences is discovering that your cigars are dried-out. Lest we not forget that keeping your cigars at the proper temperature and humidity will keep them fresh and supple, should your cigars appear to be dry, there is a solution. However, the state of dryness you find them in will determine if they can be revived or not.
If the cigars are hard, like kindling, you may as well move them to the woodpile. However, if there's even a hint of moisture left in them, they may be salvageable. The best way to test this is to gently pinch the cigar at the foot. If it crumbles or cracks you've got trouble.
Much of the flavor in a cigar comes from the oils in the tobacco. When these oils are allowed to evaporate, any other moisture in the cigar will go with it. Even if you are able to revive the cigars in question, they may lose some or all of their natural bouquet, so, you've been warned.
Re-hydrating cigars takes patience, so be prepared to wait a while before you can smoke them again. In some cases, this can take months. Ideally, you want to allow a slow absorption of moisture.
What to do
Place the dry cigars in a spare humidor or other tightly-sealed container with an appropriately-sized humidifier that is only about 25% charged. It helps to have a well-calibrated digital hygrometer/thermometer in there as well, so you can see how much relative humidity (RH) and temperature your cigars are getting. Start by placing the cigars as far away from the humidifier as possible; then move them a little closer to the device about every 3 to 5 days. I also suggest you use a clear, crystal-based humidifier. Not only do they produce a more consistent humidity, but you can actually see how much water has dissipated. Check the humidifier every few days until it's almost dried-out. If so, move on to the next step.
Add distilled water to the humidifier - about 1/3 to 1/2 full - and let the cigars rest for another week or two. Once they feel like they're coming back a little, fully refill the humidifier and let your cigars continue to rest until they are re-humidified to your satisfaction.
At each stage, always remember to place the cigars away from the humidifier and move them closer each time you refill it. Rotating them every few days will help, too. If your cigars still haven't returned to "normal" at this point, at least you can say you tried.