Things You'll Need
Instructions
Place the hygrometer and the cigars in the plastic container so that the face of the hygrometer is pressed up against the outside wall of the plastic. If the plastic is see-through, this will help you maintain watch over the cigars.
Run the sponge under the faucet for a moment and wring it out so that it is damp but not dripping water. Place it in the humidor and seal the container.
Come back in an hour or so to see what humidity the hygrometer is measuring. Most cigar enthusiasts prefer somewhere between 65% and 70%. If the humidity is too low, run the sponge under more water. If it is too much, wring it out again.
Check back around once every week and let the cigars breathe for an hour or so while you dampen the sponge again. Plastic containers can smother cigars more than wooden containers that breathe and allow small amounts of fresh air to seep in.