The term dry cleaning is a bit of a misnomer. In the United States, the dry cleaning process refers to cleaning clothes and fabrics by using a chemical solvent rather than water. The dry cleaning process is typically used on clothes and fabrics that cannot withstand the rigors of a standard home washer and dryer. It also eliminates the need for more time-consuming hand washing.
In reality, the cleaning is almost always done with liquids, however, the chemical solvent contains little or no water. While cleaning the surface of fabrics, it does not penetrate the fibers like water does in a washing machine. This process preserves the desirable qualities of many fabrics and helps to prevent shrinking and stretching.
The Commercial Dry Cleaning Process
The commercial dry cleaning process begins in your local dry cleaning storefront when you drop off your dirty clothes. Today, most dry cleaners do not have the very large and expensive cleaning equipment on-site; many will transport your laundry to a central cleaning facility. This is more cost-efficient than having machines at every drop-off location. There are several steps for each item cleaned:
- Garment Tagging: Every item is tagged with an identification number. Some cleaners use paper tags that are stapled or pinned to the garment. Others use an iron-on strip with a permanently assigned barcode for regular customers. Similar soiled garments from different customers are cleaned together and tagging ensures that your clothes are returned to you.
- Garment Inspection: Before clothes are cleaned, they are inspected for items left in pockets, rips, tears, and missing buttons. These items are returned to customers and problems are noted as issues known prior to cleaning.
- Stain Pretreatment: As part of the inspection process, the cleaner checks for stains on the clothes and treats them prior to the solvent cleaning process. If you know what caused a specific stain, it is extremely helpful to tell the cleaner to get the best results in the stain removal process. This is also the time a good cleaner removes or covers delicate buttons and trim to prevent damage.
- Machine Dry Cleaning: Soiled clothes are loaded into a large drum machine and cleaned with a water-free chemical solvent. The clothes are gently agitated in the solution which causes soils to loosen. The solvent is then drained, filtered, and recycled and the clothes are "rinsed" in a fresh solvent solution to flush away any last remains of soil.
- Post Spotting: The dry cleaning process works very well in removing oil-based stains thanks to the chemical solvent. However, other types of stains are not always removed effectively. So, all garments are post spotted to look for remaining stains. The stains are treated with steam, water, or even a vacuum to remove any remaining traces.
- Finishing: The final step includes getting the garment ready to wear. This includes steaming or pressing out wrinkles, reattaching buttons, or making repairs. Items are then hung or folded to return to the customer. The plastic bags provided are only there to help you get your clothes home without more stains. It's important to take them off right away or risk damage to your clothes from trapped moisture.
History of Commercial Dry Cleaning Chemicals
Dry cleaning has been around since Roman times when ammonia was used to clean woolen togas to prevent any shrinking that happens when wool is exposed to hot water. Next, cleaners moved to petroleum-based solvents like gasoline and kerosene which proved to be highly flammable and dangerous to use.
By the 1930s cleaners began using perchloroethylene or tetrachloroethylene, a chlorinated solvent. They are highly effective cleaners and are still used by many commercial cleaners today. Both have a distinctive chemical odor. Perchloroethylene is referred to as perc and is classified as carcinogenic to humans. In the 1990s the United States Environmental Protection Agency began to regulate dry cleaning chemicals and encourage commercial cleaners to use safer, more environmentally friendly solvents.
Green dry cleaning is based on a carbon dioxide detergent system and cleaning machines that apply pressure to draw liquid carbon dioxide through fabrics to remove soil. There is no heat involved which also makes the process more gentle to fabrics.