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What is dry cleaning?

Dry cleaning is the cleaning of fabrics with solvents other than water. Dry cleaning uses solvents that, unlike water, are able to dissolve oily stains. The solvents do not soften fibers or cause garments to shrink or stretch, and they do not affect most textile dyes and finishes.

The solvents most used in dry cleaning are Stoddard solvent, a refined petroleum product, and perchlorethylene, a nonflammable chlorinated hydrocarbon compound. Perchlorethylene is used only in special equipment in which the whole washing and drying process is carried out in a single closed unit.

The unit protects workers from the perchlorethylene fumes, which are toxic in high concentrations.

When clothes arrive at a cleaning plant, they are first tagged and sorted, and buttons and trimmings that might come off in cleaning are removed. Sometimes prespotting compounds are applied before cleaning to make spots come out more easily. The garments are then washed in the solvent in rotating perforated drums. The solvent contains a special soap or detergent and a small amount of water. The clothes are rinsed by having pure solvent circulated through them, and most of the solvent is then removed by spinning the clothes at a high speed. Finally the clothes are tumble-dried with warm air. The solvent is purified and used again.

Spots and stains that remain after cleaning are removed by a person known as a spotter. The spotter uses special solvents and other chemicals, as well as water and steam. He must first identify the fabric and the type of stain; sometimes he uses chemical tests to help him. After a garment has been cleaned and spotted, it is finished with a steam press that removes wrinkles and restores its original shape and appearance.

Dry cleaning was invented in France in the middle of the 19th century. At first the work was done by hand in small shops, and the solvent used was camphene, a lamp fuel. With the development of modern equipment and scientific methods, dry cleaning has grown into a multi-billion-dollar industry. In 1959 coin-operated automatic dry-cleaning machines were put on the market.

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