11 Cleaning Products You Should Never Mix

Oct 25, 2024

Playing chemist can be highly toxic.

When oil and water are combined, they repel one another, with a layer of oil sitting on top of the water — proof that some things just don’t mix. And while oil and water yields a rather innocent result, there are certain duos that can pose a serious threat to your health and the environment when mixed together, especially when it comes to cleaning products. Even if it isn't necessarily dangerous or toxic, you can never be sure what effect two products can have on a surface or fabric when combined.

We get it: When dirt and grime is as stubborn as can be, it’s tempting to do whatever you can to eradicate it. "People often think that if one product works, mixing it with another one will make it even better," says Carolyn Forté, executive director of the Good Housekeeping Institute Home Care & Cleaning Lab. But there are better ways to get tough jobs done — like using the most effective carpet cleaners, toilet cleaners and all-purpose sprays. So before you start to play chemist, consult this list of solutions, cleaning products and other household products our Lab pros say you should never combine.

The combination sounds like it'd be powerful, but the two should never be mixed. "Together, they produce chlorine gas, which even at low levels, can cause coughing, breathing problems and burning, watery eyes," says Forté.

When combined, bleach and ammonia produce a toxic gas called chloramine. "It causes the same symptoms as bleach and vinegar — along with shortness of breath and chest pain," says Forté. Heads up: Many glass and window cleaners contain ammonia, so never mix those with bleach.

You’ve likely heard of chloroform, and that’s exactly what bleach and rubbing alcohol make when mixed. The highly volatile compound that can cause coughing, breathing problems and eye irritation. And, yes, it can even be powerful enough to sedate when inhaled or ingested.

Have some stubborn mold and mildew in the bathroom? While it may be tempting to try these two powerful cleaners together to remove mildew, resist the urge. Many bathroom and toilet cleaners contain acids that can produce chlorine gas when combined with bleach. This can cause breathing problems and irritate the eyes and nose.

​​The best rust removal products can get the job done without the help of bleach. Together, these solutions and sprays and bleach release irritating and toxic gasses.

Lemon can be an effective household cleaning supply — use it to freshen your microwave or get stains out of a cutting board, for example — but it’s not a good companion for bleach since it’s acidic. Like commercial products that contain acid, the two can produce that toxic chlorine gas.

Oven cleaner is powerful enough, so don’t mix it with anything — not even the self-clean feature on your oven. Bleach and oven cleaner is another no-no, as it can produce chlorine gas. We already know this can cause coughing, breathing problems and eye irritation.

"I would never recommend mixing two different drain cleaners or even using one right after the other," says Forté. "These are powerful formulas, and could even explode if combined." Use one product according to package directions (typically, only half a bottle is needed per treatment). If it doesn't work, don't try another product — call a plumber instead.

While these products can be used in tandem — for instance, you can clean countertops with alternating sprays of each, rinsing the surface in between — you should never mix the two products in the same container. Combining them creates peracetic acid, which is potentially toxic and can irritate the skin, eyes and respiratory system.

This is one of the most popular DIY cleaning methods touted on social media, but our experts say to skip this “hack.” The two pantry staples are handy cleaning supplies on their own — baking soda is a mild abrasive for tough spots, like in a ceramic sink and vinegar can double as a great glass cleaner — but, contrary to popular belief, they don’t really work together. Because vinegar is acidic, and baking soda is basic, they basically just cancel each other out chemically, creating mostly water and some salt. The resulting bubbles may lift away enough to help lift some mess away or make a slow drain move again, but the mixture itself won't actually clean anything.

This combo is another rather innocent yet highly ineffective one. When mixed, vinegar and castile soap don’t make a more productive cleaner — instead, the vinegar destabilizes the soap, turning it into a chunky and oily mixture that’s hard to work with.

Brigitt is a writer, editor and craft stylist with nearly 15 years of experience. She specializes in lifestyle topics, including home, health, parenting, beauty, style, food, entertaining, travel and weddings. She has written for Glamour, People, Good Housekeeping, Women's Health, Real Simple, Martha Stewart, Apartment Therapy, The Spruce, and more.

The Guide to Getting Rid of Fleas in Your Home

How to Clean a Glass Shower Door

PSA: Stop Putting These Things in the Dryer

The Best Robot Mops in 2024

The Best Mops for Floors

NEVER Clean These Things With Vinegar

Stop Putting These Things in the Washing Machine

How to Easily Clean and Descale Your Keurig

10 Surprising Uses for Your Vacuum Cleaner

The Best Self-Cleaning Litter Boxes

PSA: Stop Putting These Things in the Dishwasher

NEVER Put These Items Down Your Garbage Disposal