I’ve always wondered how drycleaners get clothes clean without getting them wet. What do they do, put magic powder on them that makes dirt and dust disappear? Is heat involved? Radiation? Chanting? If they use magic powder, how do they get the powder and the dissolved dirt out of the clothes?
Thank you.
They use a liquid solvent, so technically they do get the clothes “wet” but just not with soap and water. The process is very similar to conventional laundering–they put the clothes into a washing machine then a dryer. How it works.
By the way, I asked this same question of my local dry cleaner. The nice lady took me to the back and showed me the equipment. It’s basically a tumble-washer and dryer, with a blue colored solvent in the washer instead of water. Below the washer, there is a window which shows the solvent being used, and when it gets dirty (you can tell by its color), they transfer it out and put it into another machine which cleans it, I think by distillation.
What I still don’t understand is why solvent is better for some clothes than water.
Detergent and high temperatures are very tough on fabric. Your clothes wear out from washing much more than they wear out from wearing them. The solvent is fairly volatile and will dry at a much lower temperature than water. I think the dry cleaning solvent also won’t wash out color. There are probably some other reasons. Here’s one take on it:
But why doesn’t the wool shrink when it’s on the sheep? Why must it be shorn before it no longer performs well?
Sheep are amazingly greasy animals. I suspect that sheep never actually get wet…
Sheep’s wool is where lanolin comes from, which is what makes the sheep so greasy, so the wool itself probably never gets permeated with water. Although I always thought it was the heat of drying rather the wet of washing that shrinks wool.
However, I’m now wondering how raw wool is prepared for making thread and yarn, since you have to wash the lanolin out somehow. I guess they must dry-clean it.
FWIW, the solvent usually used is 1.1.1 trichloroethane, which is also used in Tippex (euro White-out). It is non flammable and has a low boiling point, so easy to get out. It’s a great solvent for greasy contaminents, and so requires less agitation than a typical water/soap mixture, and is self rinsing. Also less stress while drying.
I think (although I stand to be corrected) that a lot of shrinkage occurs when water/soap mix lubricates fibres that are under tension thus allowing them to slide past each other and express the tension as recoil. Trich. does not facilitate this.
rgds