Dry-cleaning is a bit of a misnomer because, although it doesn’t involve water, it is not exactly “dry”. Instead, it uses an organic solvent rather than water to clean clothing and textiles. Different solvents have been tried in the past but most modern places use perchloroethylene or “perc”. It is particularly good at removing dirt and stains that are grease or oil-based (e.g. lipstick, some food stains), as these cannot be as easily lifted through the normal washing process using water and soap or detergent.
Thus dry-cleaning is chosen when water and soap or detergent would damage the fabrics; it is also very useful for items that are too delicate to be washed in the normal laundry and for those that would otherwise need to be washed by hand.
What Happens at the Dry-Cleaners?
Firstly, all clothing and items are tagged for identification and then inspected for any damages or loose parts (e.g. buttons and hooks), which the dry-cleaner notes down, for accountability later. Next, the garments will be examined for any stains, which will then be pre-treated with specific stain removers. This will either remove the stain or make it easier for it to be removed later in the dry-cleaning process.
How Does Dry-Cleaning Work?
Garment are grouped according to colour-fastness and then loaded into a dry-cleaning machine, which is a combined washer-extractor-dryer within a motor-driven machine. The clothes sit in a perforated, stainless-steel drum or basket, which rotates and churns the clothes around, while a constant flow of cleaning solvent is pumped into the basket, spraying and saturating all the clothes, as well as gently pounding them against the baffles of the cylinder. The dirty solvent is then pumped out through the filter, which traps all dirt, and the filtered solvent is then re-circulated and used again. For the final rinse, the basket is rinsed with fresh distilled solvent from the pure solvent tank.
Once the clothes have been through the “washing cycle”, the basket is spun rapidly to expel all remaining solvent using centrifugal forces. Next, the drying cycle involves a continuous stream of warm air circulating through the basket while the garments are turned and tumbled around. Any remaining solvent and fumes are quickly vaporised in the warm air, which is then cooled and condensed over cooling coils and any distilled solved extracted from this air current is returned to be re-used in future cycles.
Finally, there will be a “post-spotting” phase where the garments are examined again for any remaining stains and then the appropriate stain removers and methods used to tackle them. Most stains and spots should be removed but occasionally, some marks will be resistant. These include tannin stain that have been set by heat and time, stains from foreign dyes, areas where the original dye has been stripped or faded and any spots that have been bleached out or faded by the sun.
The Finishing Touch
Before allowing the clothes to be collected, they will undergo a “finishing” phases where they will be pressed, steamed and ironed and reshaped, to that they look their best. Many professional outfits will also make any necessary repairs, so that your clothes are presented back to you in top condition.
NOTE: make sure you remove the plastic covers and hang your clothes up to air in a well-ventilated area for a day or two after you get home, to make sure that all solvent fumes have dispersed, as these can be potentially toxic to very young children, pets and those with respiratory weaknesses.