“Laundry stripping”: what the murky water really shows

You’ve probably seen the videos: a bathtub of “clean” towels soaking in hot water turns grey, then brown, and the caption says this is what’s been hiding in your laundry. It’s oddly satisfying to watch. But what’s actually coming out, does it matter for your skin, and is a bathtub full of cleaning chemicals the best way to deal with it?

What laundry stripping is

Laundry stripping means soaking already-washed laundry, usually towels and bedding, in a bathtub of hot water mixed with borax, washing soda and laundry detergent. The idea is to dissolve build-up that normal washing leaves behind.

Consumer Reports, which tests laundry appliances and products, explains what each ingredient does. Washing soda, or sodium carbonate, has a high pH, meaning it’s strongly alkaline. It acts as a cleaner and a water softener, and their test engineer describes it as potentially caustic. Borax is a mineral used as a laundry booster. The detergent adds more cleaning power, and the heat speeds everything up.

What the murky water actually shows

The grey water is the whole appeal, so it’s worth being clear about what it is. According to Consumer Reports, it comes from three main things:

• Leftover detergent, especially if you’ve been using more than the recommended dose
• Fabric softener, which is designed to coat fibres and builds up over time
• Minerals from hard water

There’s a fourth ingredient in that murky soup that the videos rarely mention: dye. A long, hot, high-pH soak pulls colour out of fabric, which is one reason the water can look dramatic even from reasonably clean towels. The colour of the water tells you what the soak dissolved, not how dirty your laundry was.

Hard water, minerals and your skin

Hard water is water rich in calcium and magnesium. Health Canada’s drinking water guidance explains that hard water needs considerably more soap to make a lather and leaves scale in pipes and appliances. It considers water above 200 mg/L of hardness “poor” but tolerated, and water above 500 mg/L unacceptable for many household uses. If your kettle gets a chalky crust, that’s hardness scale.

Consumer Reports lists mineral build-up among the things a stripping soak pulls out, so some of those minerals clearly end up in fabric over time. Hard water also makes detergent work less efficiently, which tempts people to use more, and more detergent means more to rinse out.

Does it matter for skin? The research is genuinely mixed:

• A 2016 study of 1,303 three-month-old babies in the UK found that visible eczema was more common in homes with harder water. That’s an association, not proof that hard water causes eczema.
• A randomized trial of 336 children with moderate to severe eczema, all living in hard water areas, installed water softeners in half the homes. After 12 weeks, eczema improved about the same amount with or without a water softener.

So, softer water may matter for some babies’ risk of eczema, but softening water didn’t treat existing eczema in that trial. And neither study looked at laundry build-up specifically. Health Canada also notes that home water softeners add sodium to treated water, something to know if you’re on a low-sodium diet.

The safety concerns with the recipe

The stripping recipe uses products that deserve more respect than a viral video suggests.

Borax. Health Canada explains that borax is a mineral that may produce boric acid. Its draft assessment proposes that boric acid may harm development and reproduction when used in products that can be inhaled, swallowed or touch the skin, with children and people assigned male at birth at highest risk. It advises reading labels for boric acid, borax or borates, following directions and storing these products out of children’s reach.

Washing soda. It’s strongly alkaline. Consumer Reports recommends gloves and a mask to avoid skin contact and breathing the dust. That’s a lot of bare-hand exposure for anyone with hand dermatitis or eczema.

Heat and pH on fabric. A long, hot, alkaline soak can strip dye and damage fabrics sensitive to heat and high pH, according to Consumer Reports. Colours fade and delicate fibres weaken.

Residue after the fact. Soaking laundry in a concentrated mix and then washing it once may leave some of that mix behind, which is the opposite of what sensitive skin needs.

A gentler way to deal with build-up

If your towels feel stiff, smell musty or don’t absorb well, you can remove build-up without the bathtub. Consumer Reports’ testers suggest:

• An extra rinse-and-spin cycle with no detergent in a front-loader
• A deep soak-and-spin cycle with no detergent in a top-loader

Then prevent build-up so you don’t need to repeat it:

• Use the recommended amount of detergent. The American Academy of Dermatology’s self-care advice for eczema is specific: only the recommended amount, and enough water for rinsing.
• Cut back on fabric softener, or skip it. It’s the one laundry product meant to stay on fabric.
• Don’t overload the washer, so clothes can move through the rinse water.
• Consider hard water if build-up keeps coming back. Your water supplier can tell you your water’s hardness, and a private well can be tested.

If you’re choosing a detergent for sensitive skin, you can browse laundry products the panel has reviewed.

When to think beyond laundry

If you’ve been blaming residue for itchy, red or flaky skin, and a simpler routine with the right dose and an extra rinse doesn’t help within a couple of weeks, the laundry probably wasn’t the main problem. See your doctor or pharmacist, especially if the rash is spreading or keeps coming back.

What to remember: laundry stripping mostly removes leftover detergent, softener, minerals and dye, and the grey water isn’t a measure of how dirty your laundry was. Borax and washing soda carry real cautions, especially around children and sensitive skin. An empty rinse cycle, the right detergent dose, less softener and a roomy washer do the same job more gently.