There are many different variations of closet dehumidifiers and different brands, some of them absorb the moisture using special drying crystals which are called Silica gel. These special crystals protect your books, clothes, private materials and other items from becoming musty or moist, giving them a longer life span inside your closet and putting your mind at ease when you are storing them away. Silica gel is contained inside the closet dehumidifier and require no special instructions, you just place it inside and it does the work of protecting your valuable items. You also have the small more ordinary kinds of closet dehumidifiers. These types of dehumidifiers do not work with crystals but instead contain a small fan which keeps your closet and small spaces free from mold spores, heavy dust build up and moisture that causes metal objects to rust. A fan type closet dehumidifier is  small, easy to maintain and works wonders inside any small space or closet in your home. They are also quite energy efficient so they will not cost you much to operate.  In addition, if you move homes, most are portable dehumidifiers that can be taken with you. Every home should have at least one closet dehumidifier to keep their stored away items safe from the  harm of excessive moisture.