Dry Cleaning

A lot of people when they think of dry cleaning think of jets of dry cleaning gas being blown into garments with no liquid involved whatsoever. But the truth is, dry cleaning is almost the same as normal cleaning, just a different solvent is used. The machine used even resembles a household washing machine.

The key difference between dry clean and normal washing is the liquid used. Most dry cleaning industries uses tetrachloroethylene due to its superior dissolving power compared to other solvents like hydrocarbon based ones or silicone based ones. But the downside of tetrachloroethylene is that it is toxic to the environment and also a likely human carcinogen. 

Why dry clean?

Garments made of wool have two problems when washed in a normal washing machine with normal detergent. The first problem is that the wool fibers have many little hooklike flakes that cause the wool to hold together. This is usually a good thing but with excessive agitation in water the hooks make the wool stick together more and thus shrinkage occurs. The second problem is that most detergents contain enzymes that are good for dissolving grease stains. But since wool is also made of protein, the enzymes also dissolve parts of the wool leaving holes in the garment. 

Image Citations: 

N.d. Care of Sheepskin and Wool. Web. 10 May 2016. <http://home.cogeco.ca/~bhemphil/care.html>.

N.d. United Machines. Web. 10 May 2016. <http://www.laundrymachines.in/dry-cleaning-machines.htm>.