The dry cleaning process is similar to how people typically wash clothes at home, except items are not cleaned with water but with a chemical solvent. A dry cleaner will inspect items for stains and pretreat them with the correct type of solution.
After items have been pretreated, they're put into a machine similar to a home washing machine. The machine is a large steel basin with holes that allow the cleaning solution to mix throughout the load. The basin spins to remove dirt and cleaning solution. Many dry-cleaning machines combine a washing section and drying section. After the clothes are cleaned, they're placed in the drying section so warm air can circulate and dry them, removing any solvent left in the fabric.
The chemical solvent often used by a dry cleaner is known as tetachloroethylene or perchloroethylene, also referred to perc. The chemicals tend to leave an odor, are flammable and considered to be environmentally detrimental.
Many cleaners have changed their type of solvent and are using environmentally safer alternatives. The "green" dry cleaning technique uses carbon dioxide. When carbon dioxide is in liquid form, there must be a high amount of pressure for it to work correctly. Dry cleaners that use this method have a machine with a pressure chamber that cannot be accessed while the machine is operating.