How do dry cleaners clean clothes?

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The YouTube channel Today I Found Out digs into the mystery of what happens to your clothes after you drop them off at the dry cleaners. And the video also provides a detailed breakdown of the history of dry cleaning too.

This video doesn’t go into the history and chemistry behind dry cleaning, but it’s 100% more footage of the actual process rather than just someone talking about it:


No I’m pretty sure this better represents the actual dry cleaning process.


I’ve worked for years on the related question, how does science clean dry cleaners?


tl;dr: with chemicals

I was expecting some science of how the chemicals work and the engineering behind the machines.


This process seems a lot more intense than a trip through my wimpy little home washer… what is it that makes this gentler than washing at home?

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Water is a chemical. So are the surfactants in any commercial laundry detergent or soap.

Water isn’t great at removing stains, because the stains are mostly made of non-polar molecules that do not dissolve easily in a polar liquid like water. So for water to work as a cleaning solvent, you need to add soaps and detergents, and you need to make it hot, and you need to agitate it. As well, most clothing fibres are made of polar molecules, so water interacts far more strongly with the fabric than the stains, which can cause the fibres to swell, stretch, distort, and degrade.

Dry cleaning uses non-polar solvents, like tetrachloroethylene, petroleum, or supercritical CO2. They are better at dissolving and removing the stains, don’t require as much detergent, don’t require as high a temperature, and don’t interact with or damage the fabric. But: far more expensive, and except for scCO2 they all have serious environmental issues.


That Youtube voice. He sounds like an auctioneer.

Why bother with such expensive measures when you can just crowdsource the problem to the liver of everyone in the affected area? Boisterous children, especially, have the energetic metabolisms needed for a salubrious effect!

Yours respectfully,
Andrew Ure

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lots and lots of nasty chemicals.

Solid explanation, you looking for work?

For what it’s worth, the most common chemical used for dry cleaning, perc, can be recycled and re-used many times. Unfortunately when it does need to be disposed of, it’s a hazardous material and pretty nasty, indeed.

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Super unfortunately, it’s only been “hazardous waste” since about 1970ish, prior to which hazardous waste was not quite regulated. That leaves about 20 years where people did all sorts of things with the stuff. The Navy used to wash planes with it over gravel pads. :frowning:

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Holy crap. Guh.
I want to apologize to the aquatic life of Washington Courthouse, Ohio, where my great-grandfather had a dry-cleaning business for many years.

Thanks! Well, I’ve got tenure. And more work than I have time for, for at least a couple of years. Part of that work involving researching better ways to explain concepts like interactions between polar and non-polar molecules.



Okay good, you keep sending them my way as well informed as that, and I’ll find them work.

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Those two paragraphs are far more informational than anything in the 9 minute video.


As much as I am truly interested in the topic, I can’t stand this person. In pursuing of a better appeal he comes across just too fucking generic.

I mean, hell man, can you be a bit more authentic?