Dry cleaning is the happy result of an accidental spill. Jean Baptiste Jolly owned a large scale dyeing company in the mid 19th century. One night in 1855, his maid accidentally overturned his kerosene lamp onto a stained tablecloth. The next morning he realized that the tablecloth was clean and Jolly quickly decided to capitalize on the concept.

As part of his company, Jolly began offering cleaning services, which he named dry cleaning. This was not because the clothes he cleaned never got wet, but rather because they never got wet with water. Early cleaners included some fairly toxic substances and could be quite dangerous.

For example, Jolly used both gasoline and kerosene in order to perform his dry cleaning. Later, solvents like trichloroethylene and carbon tetrachloride could also have nasty side effects. Since the 1950s, the most commonly used dry cleaning substance is perchlorethylene, also know as perc.

The way modern dry cleaning works is that clothes are first tagged and pre-treated for any visible stains. They are then placed into a large machine, rather like a large washing machine. The clothes spin in the machine, which also administers up to 200 gallons (757.08 liters) of perc in as little as eight minutes, the typical cycle length. The next machine cycle drains the perc, and spins the clothing.

Most dry cleaning machines also have a heating element, so they are essentially washer and dryer combined. After the perc is siphoned off, clothes are heated with circulating warm air, so they are dried. Once removed from the machine, the next process in dry cleaning is post stain treatment.

In dry cleaning, a good cleaner knows to check the clothes for any remaining stains. These will be treated again with solvent or even water. A dry cleaning service may also perform a little mending of clothes, replacing buttons or sewing up small rips. The clothes are then hung on hangers and bagged with plastic, awaiting pick up from their owners.

Concern in recent years over perc, which is clearly not environmentally friendly, has led to new “green” dry cleaning methods. Instead of perc, some green dry cleaning cleaners have changed to solvents made from carbon dioxide. Carbon dioxide can only be in liquid form when exposed to pressure, so the dry cleaning machine must be able to provide a pressurized environment in order for the carbon dioxide to work properly. One machine, Micell’s Micare, features a pressure chamber and pressure door in order to appropriately clean the clothes.

Green dry cleaning is considered gentler on clothes. It is also certainly more environmentally sound. With greater interest in pro-environment methods in dry cleaning, green dry cleaning may ultimately replace perc dry cleaning.