Laundering clothes uses water and detergent to remove dirt, stains and odors from the material, while dry cleaning uses a solvent other than water. Early dry cleaning used petroleum-based solvents, such as kerosene, gasoline and carbon tetrachloride. Since World War II, nonflammable perchlorethylene has been the solvent of choice for dry cleaners, according to HowStuffWorks.
While the name of the process is dry cleaning, it is not a dry process. Clothing is placed in a large machine, similar to the washing machine used at home. Instead of filling with water, the machine fills with the solvent. Once the clothes finish the cycle, the dry cleaner dries, shapes and presses them.
While perchlorethylene remains in use in 85 percent of dry cleaners, there are growing concerns about its use. It is a toxic chemical and potential carcinogen, according to NYC Recycles. New York City has banned the installation of new perc machines in cleaners located in residential buildings. It requires companies that continue to use perc as a solvent move to nonresidential buildings by the year 2020.
Some dry cleaners are using alternatives. Computer-controlled machines allow wet laundering of practically all fabrics, with the exception of wool, without causing the garment to shrink or lose its shape. Liquefied carbon dioxide is a safer option that some dry cleaners are using. Others are choosing a silicon solvent, which degrades to water, sand and carbon dioxide after use.