Analog hydrometers may be calibrated in two ways :
The usually suggested and most exact calibration technique is to put the hygrometer coupled with salt solution inside a plastic box of small proportions . A small quantity of salt needs to be taken and moistened such that it remains damp but does not dissolve . The hygrometer and salt should then be placed in a sealed plastic box . At the end of 8 hours humidity of the box should be 75 %. Needle of the hygrometer maybe adjusted with a screwdriver , at the rear , to mark 75 % humidity .
On the other hand , you might get rid of the hygrometer from the humidor , drape the hygrometer in a carefully damp cloth , and after about an hour regulate the hygrometer on the back with a screwdriver to about 96 % relative humidity .
The humidifier must be placed on a plate and moisturized it with propylene glycol solution ( applicable for a sponge-based humidifier ) or distilled water .
Humidifier is left in the solution for about an hour and it absorbs liquid . Once it has absorbed an appropriate amount , the humidifier needs to be shaken in order to ensure that the liquid that was not riveted would be eliminated . The next step is to make dry the humidifier with a piece of cloth .
A cloth placed in distilled water should be used to wipe the walls of the interior of the humidor , divider and trays .
A glass of distilled water is placed in the humidor for three days . If you heat the water in a microwave before placing it into the humidor then the process takes only about a day before the humidor starts functioning . Basically the walls of the interior must absorb enough humidity .
A humidor that is well filled ideally must be aerated at the least about once every two weeks to supply it with fresh air on a regular basis . Temperature ranging between 64-70 ° F ( 18-21 ° C ) is deemed perfect .
Temperatures veering beneath 54 ° F ( 12 ° C ) may cause the aging process of the cigars to be seriously damaged . Thus it is only up to a point that cold wine cellars can serve for the purpose of cigar storage .