The best place to refresh a cigar is in a humidor. A humidor allows you to keep a stable humidity setting that will help reintroduce moisture to the cigars and bring back a degree of freshness. But not everyone wants to invest in such equipment. The key is to introduce your cigars to a moist environment. Once cigars dry out, it takes patience to refresh them and, even if you succeed, the quality is noticeably diminished. If the cigar is dried out to the point it crumbles, even a humidor won't help; you will need to dispose of them.
Remove the cigars from the packaging and wrap them in a paper towel.
Soak a sponge in warm water and ring it out. Place the sponge in a Ziplock bag and use scissors to cut a few small holes in the bag.
Place the cigars at one end of the cedar box and the sponge at the other end. Close the box and make sure the lid is closed tightly.
Check the sponge every day. Take it out of the Ziplock bag and place in a new one after washing out the sponge and re-wetting it. Make sure you wring out the sponge before placing it in the Ziplock bag and don't forget to cut holes in the new bag. This will help prevent mold from growing inside the cedar box. It will take about four weeks to freshen the cigars so you can smoke them. After that, you should still store the cigars as described, changing the sponge each day, for up to six months to keep them fresh. After six months the cigars will go stale regardless of how you store them.