How Does Dry Cleaning Work?

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Dry cleaning is a process of cleaning clothes that uses a solvent instead of water. The solvent is usually a petroleum-based chemical, and the clothes are tumbled in the solvent to remove stains. The solvent is then removed from the clothes, and the clothes are pressed to remove wrinkles.

When people drop off their clothes at the dry cleaner, they don’t tend to hang around and ask the workers what sort of magic they wield to eliminate tough stains from the most delicate fabrics. Most customers simply come back 2-3 days later, expecting a perfectly pressed and cling film-covered outfit that is crisp and ready to wear. However, dry cleaners are not magicians, and the process of dry cleaning is surprisingly simple. The question is, how does it actually work?

Short Answer: Rather than using water, dry cleaning relies on a different non-water-based solvent to remove stains, followed by additional processing and pressing to keep delicate clothes looking brand new.

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The Science Of Dry Cleaning

As most of you know, cleaning your clothes in a regular washing machine is perfectly acceptable for most types of clothes, provided you keep the colors separate. After loading them into the washing machine and adding detergent, water slowly filters in and the machine begins to churn, eliminating stains through friction and the effects of water as a universal solvent. However, not all substances are water-soluble, meaning that regular washing won’t be able to eliminate them from your clothes. Furthermore, certain types of material do not react well with water, so they shouldn’t be put into a washing machine. This is where dry cleaning comes in.

The foundation of dry cleaning is the use of a petroleum solvent, rather than relying on water. The first person to recognize the potential of a petroleum solvent lived roughly two centuries ago, and accidentally discovered dry cleaning by spilling kerosene on a greasy item of clothing. Seeing that the pesky stain was eliminated, he established the first dry-cleaning service in Paris after experimenting with different petroleum-based substances.

Today, the same tradition is largely intact, because there is no water in petroleum, so those delicate fabrics are protected while they are being cleaned. However, kerosene is extremely flammable, so in the past 200 years, many other options have been developed. Most notably – and most popularly for decades – perchloroethylene was used for many years because it was not flammable and highly effective. Affectionately shortened to “perc”, even this solution was found to be potentially hazardous – and carcinogenic – so for the past two decades, new dry-cleaning solvents have been growing in popularity.

Also Read: How Does Soap Clean Dirty Clothes?

The Process Of Dry Cleaning

Much like a regular washing machine, your delicate suits, dresses and ties are added to a front-loading washer, but instead of adding water to the machine, the petroleum-based chemical is added. The fabric is tumbled, relying on friction to scrub out the difficult stains with the “perc” or other solvent.

After a certain amount of time, an extractor removes this chemical from the clothes and machine, along with the dirt and grime, leaving your clothes perfectly clean. The solvent is then converted back from liquid into gas, meaning that it can be reused – a major benefit for dry-cleaning companies, in terms of cost.

Unfortunately, this “dry” cleaning process doesn’t remove every stain, so small amounts of “wet” or “dry” spot-removing agents are applied by hand for the toughest spots. Following this, your most precious clothes are sent through a high-powered pressing machine, which provides the crisp edges and “brand-new” feeling to your dry-cleaned clothes.

Also Read: Why Do Clothes Shrink When You Wash Them?

Why Can Some Things Not Be Dry Cleaned?

As mentioned above, certain materials are not recommended for traditional washing, such as cashmere, wool, silk, muslin, suede, soft leathers and clothes with intricate embroidery or beadwork.

For some of these materials, the use of water causes the fibers to denature and loosen, and it can be difficult (or impossible) for them to assume their original shape. This is true for wool and silk, particularly if the article of clothing is composed of more than 60% of those fiber types.

When it comes to muslin, the fabric is simply too delicate for the rigors of a regular washing machine, and would likely tear in the process, rendering it useless.

For suede and soft leather items, stains can do significant or permanent damage, but adding water could do more damage or result in spotting of the fabric. Dry cleaning is required to lift the stain without making things worse. However, certain types of suede require even more careful processing, so only select dry-cleaning establishments can handle the task.

Finally, if your clothes are intricately woven, embroidered or contain beads, sequins etc., you will need to use a dry cleaner because the vigorous rubbing and friction of a traditional water will likely damage or tear the fabric. In this case, you also want to go to an experience dry cleaner that you trust, as even dry cleaning can do damage to these fragile items.

Dry Cleaning In The Future

Petroleum-based solvents have worked for centuries now, but there are always advancements, even in this rather static field. Some of the newest ideas for dry cleaning include the use of CO2 as a solvent, which has proven to be extremely effective and much less dangerous for employees of dry cleaners than using the carcinogenic “perc”. Unfortunately, the machinery needed to convert CO2 from gas into liquid is expensive, so this is only available in select, high-end dry cleaning establishments.

The only thing we know for sure is that people will always have fancy weddings to go to, as well as delicate clothes that need to look pristine for the big day. Where there is a demand – even in the seemingly boring world of dry cleaning – innovation is bound to follow!

References (click to expand)
  1. Toby, E. M., Jr. (1943, October). Petroleum Solvents. Industrial & Engineering Chemistry. American Chemical Society (ACS).
  2. Dry cleaning - New World Encyclopedia.
  3. Carbon dioxide cleaning - Wikipedia. Wikipedia
About the Author

John Staughton is a traveling writer, editor, publisher and photographer who earned his English and Integrative Biology degrees from the University of Illinois. He is the co-founder of a literary journal, Sheriff Nottingham, and the Content Director for Stain’d Arts, an arts nonprofit based in Denver. On a perpetual journey towards the idea of home, he uses words to educate, inspire, uplift and evolve.

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