How Dry Cleaning Works

How Dry Cleaning Works

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Dry cleaning has been a little bit of a mystery for many people. They take their garments to a cleaner, then pick it up. We all do that without really knowing how dry cleaning works. In this article, we will give you a brief overview of it and how it works.

How Dry Cleaning Works

Although there is the mystery of dry cleaning and how it works, the process is actually quite simple. However, the risks involved are pretty high.


Contrary to popular belief, dry cleaning dates back to ancient times. Humanity has been cleaning delicate items since the time that Vesuvius erupted circa AD fabric becomes misshapen and shrinks when washed in water. Fullers (professional clothes cleaners) were known to use Ammonia Lye and Fullers Earth. Fullers Earth is a clay which is very good for absorbing sweat dirt and grease stains.  In folk law, the earliest reference to anything resembling modern methods of dry cleaning refers to a maid who accidentally spilled Kerosene on a greasy tablecloth, the kerosene evaporated, and grease spot was noticeably lighter.  After this incident, there have been many tests performed to see what other solvents were effective at removing difficult stains. These chemicals included Turpentine, White Spirits, Kerosene, and other petroleum-based products such as Gasoline and Camphor oil.

First Commercial Dry Cleaner

The first commercial dry cleaner is said to be the company Jolly-Belin of Paris.  They opened up in 1825, and of course, at that time, fashion was of great importance to Parisians. At this time, people soaked the delicate clothes in massive vats of turpentine. Turpentine was evaporated in what could be classed as the forerunner of today’s Air Dryer.  At about the same time a US tailor come inventor, Thomas Jennings, worked out how dry cleaning works, and patented the process and called it dry scouring. That happened in 1821, and Jennings, who was Afro American, ran a very successful tailoring and dry-cleaning business in New York.

How dry cleaning works

The problem with petroleum by-products was the tendency to catch fire, so they sought better alternatives.  Michael Faraday, an English chemist, first created PCE (perchloroethylene) in 1821. It only becomes common in the US after William Joseph Stoddard; an American dry cleaner further developed PCE as a dry cleaning product in 1930.  Its use grew during late 19930 to early 1940 because of the second world war and the incumbent fuel shortages.

Early Solvents

There were a variety of highly flammable solvents used in the 1930’s such as kerosene, Benzene, Turpentine, Gasoline, and petroleum. So came the invention of synthetic non-flammable substances. They included; perchloroethylene (PCE) and decamethylcyclopentasiloxane (Green Earth), which are still in use today.  Detergents are regularly used to aide the removal of dirt and. Stains. They Aid dry-cleaning in 3 ways.

  1. Carrying moisture to aid in the removal of water-soluble stains.
  2. The soil and debris will float after the removal so it cannot continue to be absorbed again.
  3. It can penetrate the fabric and act as a spotting agent so that the solvents can remove the stains.

How Dry Cleaning Works – Process

The machines for dry cleaning consist of four essential parts, which, over time, have significantly improved.

  1. The holding tank, which holds the chemical.
  2. A pump to circulate the solvent through the machine
  3. Filters to remove the dirt from garments and debris from solvent
  4. A cylinder or basket or drum to contain the garments

During the dry cleaning, the pump draws solvent from the header tank and sends it through the filters to remove any impurities from the solvent. The clean solvent then enters the cylinder and soaks the garments removing any dirt and stains. The solution then travels back to the header tank to start the process again. It repeats this as many times as necessary.

After the garments complete the cleaning cycle, the machine will then commence the extraction cycle. The drum/cylinder will rotate to extract the solvent going faster and faster, much like a conventional washing machine.

After this cycle finishes, the drum stops moving the garments are then removed and put into a drier, or if it is an integrated machine, put onto a drying cycle.  The excess solvent is collected and returned to the holding tank.

That is the basic principle of How Dry Cleaning Works. However, there are different machines that will do it in slightly different ways.

Environmental and Health

Perchloroethylene (perc), even though it is the most popular choice for dry cleaning, is dangerous to both health and the environment. That statement is according to the Occupational Safety and Health Administration (OSHA).  Coming into contact with perc puts employees at high risk of health problems. Loading and unloading dry cleaning machines have proven to increase exposure levels exponentially. Alternatively, if the removal of the items is before the drying process completes on a dual-action machine.  Also, when changing or cleaning filters or lint deposits and during general maintenance operations.

Overexposure occurs when people have their clothes dry cleaned regularly, too. The symptoms include; mild memory loss, altered visual perception, drowsiness, dizziness, loss of coordination, and blistering of the skin after prolonged contact.  Employees in the dry-cleaning business also face increased risks of certain types of cancer.

According to the National Library of Medicine, long term exposure may lead to certain types of cancer. They include;

  • Cervical
  • Bladder
  • Esophageal
  • Multiple myelomas
  • Non-Hodgkin’s lymphoma

There are also links to breast cancer.  Damage to the central nervous system, kidneys, liver, and lungs may develop.

How Dry Cleaning Works – Environmental Study

A 2014 study appearing in Environmental Health Perspectives, specifically examined the risk of bladder cancer in people working with or exposed to perc.  Studies show that strong correlations between dry-cleaners who use perc as a solvent and an increased risk of bladder cancer.  Even after taking account of smoking cigarettes and the risk factor that it poses, this held true.

Unfortunately, perc levels are high in the water, air, and soil in the environment surrounding production sites, and dry-cleaner shops.  According to the Agency for Toxic Substances and Disease Registry, the dry-cleaning industry accounts for most of the perc found in the atmosphere.  The compound takes a long time to break down in the atmosphere so it can travel considerable distances.

Perc can enter the water system by liquid waste, which may contaminate it with the solvent.  Perc evaporates quickly in water, and the leftovers continue to breakdown slowly in the water.  Where the chemical concentrates after seeping out at waste disposal sites, it will also break down slowly.


Although there are many industrial chemicals used, you can have great dry cleaning results at home with other, less dangerous chemicals such as Isopropanol. If you are looking for ways to spot clean fabrics while spring cleaning, then these products can do an amazing job. Look out on our blog page for instructions on how to spot clean furniture with chemicals that you can easily buy.


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