For at least a century, hydrogen peroxide has been widely used as a super cleanser by everyone from housewives to orthopedic surgeons. But which uses are still backed by solid science today, and which ones should you consider outdated — or even dangerous?

Spoiler alert: Hydrogen peroxide is no longer recommended for wounds or skin care because doctors have discovered it can lead to dangerous complications and can slow healing time, but there are still lots of ways it can be useful and beneficial to you.

Hydrogen peroxide may seem old-fashioned in its dowdy brown bottle — but it’s definitely not a natural home remedy. It’s a household chemical.

True, it differs from water only by the addition of one extra oxygen molecule. But that extra molecule turns it into a powerful oxidizer. It’s the reason hydrogen peroxide is such a versatile cleanser, and it’s also the reason you need to use it cautiously on people and pets.

Hydrogen peroxide breaks down quickly and easily when it comes into contact with air or water, so it’s considered safer than chlorine chemicals.

According to the Centers for Disease Control (CDC), hydrogen peroxide kills yeasts, fungi, bacteria, viruses, and mold spores.

The CDC lists specific concentrations you need and how long you need to let them sit to kill different organisms.

Here’s how to use this common chemical to cleanse your body and your home safely.

1. Clean your dishwasher

To eliminate mold and mildew in your dishwasher, spray the intricate parts of your dishwasher where moisture can linger long after a cycle is complete — in the pleats of rubber seals, traps, and crevices of the utensil basket.

A 2016 study of residential dishwashers found that 83 percent of the dishwashers they tested were positive for fungi, and 47 percent of dishwashers tested contained the black yeast E. dermatitidis, which can be harmful to humans. E. dermatitidis was detected primarily at the dishwasher rubber seals.

Or if you feel like giving this hardworking appliance a spa day, use hydrogen peroxide, baking soda, and essential oils to make a scented dishwasher “bomb.”

2. Scrub your sink

Many home care blogs recommend this trick to clean your kitchen sink: Wet the surface of your sink, then scrub it with baking soda sprinkled onto a sponge. When you’ve scrubbed the whole surface, pour 3 percent hydrogen peroxide over the surface and allow it to sit before rinsing it clean.

3. Disinfect counters and cutting boards

According to The Ohio State University Extension, cleaning counters with undiluted hydrogen peroxide is effective at killing E. coli and Salmonella bacteria on hard surfaces like counters when it’s allowed to sit on the surface for 10 minutes at room temperature.

Renowned renovator Bob Vila’s website advises a 10-minute soak in 3 percent hydrogen peroxide to kill germs on wooden cutting boards.

4. Wash veggies — and extend their shelf life

Organic gardeners recommend using 1/4 cup of 3 percent hydrogen peroxide per gallon of water to help remove bacteria from vegetables. If you’re washing delicate-skinned vegetables like lettuces, just soak for 20 minutes and then rinse.

Carrots, potatoes, and other tough-skinned veggies can be soaked 30 minutes before rinsing and drying. Because bacteria can cause vegetables and fruits to turn brown, a hydrogen peroxide bath is believed to keep them fresh longer in your fridge.

5. Scour cookware

If your cookie sheets, pots, and pans have a baked-on layer of brown, Jill Nystul of the blog One Good Thing recommends sprinkling them with baking soda, then spritzing the soda with 3 percent hydrogen peroxide will restore them. Allow them to soak for 1 to 3 hours before wiping off the mess.

6. Get rid of garbage can germs

After washing the garbage can with soap and water, spray the whole container with a 1:1 solution of hydrogen peroxide and water. Let the trash can sun-dry for several hours. Just as peroxide cleans surfaces, it’ll help remove germs from your trash can.

7. Deep clean your toilet

According to the CDC, hydrogen peroxide is effective at removing microorganisms, including bacteria, yeasts, fungi, viruses, and spores, making it a good choice for cleaning your bathroom.

To clean your toilet, add 1/2 cup of 3 percent hydrogen peroxide to your bathroom bowl to kill germs and brighten the surface of your toilet. You’ll need to leave it in the bowl for 20 minutes to get the full benefit.

8. Shine mirrors and glass surfaces

Spray a 1:1 solution of water and hydrogen peroxide onto glass surfaces, then wipe with paper towels, a lint-free cloth, or newspapers for a streak-free clean.

9. Kill mold and mildew

Mold and mildew can build up quickly in the moist environment of a shower stall.

To kill them without having to breathe in toxic bleach fumes, spray with undiluted 3 percent hydrogen peroxide and allow it to sit for 30 minutes. Rinse. The peroxide will kill the mold and mildew, but you may still need to remove the stains they left behind.

10. Whiten old porcelain

If your porcelain pedestal sink has yellowed, you can brighten it by scrubbing the dampened sink surface with baking soda, then scrubbing with a sponge saturated with 3 percent hydrogen peroxide.

11. Foam away soap scum

For weekly cleaning of a fiberglass shower and tub, make a foaming paste from 1 cup baking soda, 1/4 cup white vinegar, plus a tablespoon or two of hydrogen peroxide. When the bubbles subside, scrub the surface of the shower with the mixture.

Take care! If you’re using straight peroxide, wear gloves to protect your skin. Hydrogen peroxide can cause redness and burning.

12. Remove stains

The Environmental Working Group recommends hydrogen peroxide as an effective way to remove grass stains, blood stains, and drink stains like fruit, juice, and wine. Try dabbing the cleaner on the reverse side of the fabric to start.

13. Brighten dingy whites

Nystul also has a solution if your T-shirts, sheets, and towels have taken on a grimy, gray hue.

Make your own oxygen-bleach by combining 1/2 cup washing soda — hint: It’s not the same as baking soda — and 1/2 cup hydrogen peroxide. Start the cycle, allow the washer to fill, and soak the clothing for a couple of hours before finishing the cycle to whiten and sanitize.

Wait! Swab a swatch first. Before you try hydrogen peroxide on any fabric, test a small, out-of-the-way section for color fastness. Use extra care with vintage fabrics: The Smithsonian Institution’s fabric conservation experts say peroxide can bleach and weaken fibers.

14. Sprout healthy seeds

Numerous studies have shown that soaking seeds in 1 to 3 percent hydrogen peroxide can soften the seed coat and start germination. If you want to increase the chances of a good plant yield, you can soak seeds in hydrogen peroxide for 20 minutes before planting.

15. Clear algae from your pond water

If you have a water feature or koi pond, you can safely treat the water to reduce or remove harmful algae. Gardening experts at Get Busy Gardening used 1/2 cup of 3 percent hydrogen peroxide to clear a 90-gallon pond.

16. Treat plants with fungal infections

If your garden vegetables are suffering from powdery mold or other fungal infections, you can spray them with a hydrogen peroxide solution to rid them of the fungus.

Mix 4 teaspoons of hydrogen peroxide in a pint of water and spray the plant. Stronger concentrations could burn delicate leaves, so don’t use it at full strength.

Most veterinarians no longer advise using hydrogen peroxide to clean your pet’s wounds, no matter how small the injury is.

17. Induce vomiting for poisoned dogs

If your pet has eaten something poisonous, your veterinarian may advise you to use hydrogen peroxide to make the animal vomit.

Because hydrogen peroxide is dangerous for your pet to ingest, it’s critical that you talk to your vet or a poison control center before attempting to induce vomiting with this method.

18. Clean out the litter box

To eliminate odors and disinfect your cat’s litter box, empty the litter, wash the container with soap and hot water, and then spray thoroughly with full-strength peroxide. Let it sit for 15 minutes before rinsing, drying, and replacing the litter.

Fish tank warning!

Some aquarium hobbyists use hydrogen peroxide to control algae and clean their tanks, but talk to a fish veterinarian before putting hydrogen peroxide in your tank. While hydrogen peroxide degrades rapidly in water, research suggests that some species of ornamental fish, including gourami and suckermouth catfish, can’t tolerate it.

The Food and Drug Administration (FDA) classifies hydrogen peroxide as “generally recognized as safe” (GRAS) for humans at low doses. But the FDA warns that getting hydrogen peroxide on your skin may cause irritation, burning, and blistering.

If you get it in your eyes, it could cause burning or abrasion of your cornea.

Breathing it in at higher concentrations could also cause irritation of your airways, tightness in your chest, hoarseness, or shortness of breath. And swallowing hydrogen peroxide, especially at higher concentrations, can cause vomiting, inflammation, or damage to hollow organs.

Take it out of your first aid kit

Hydrogen peroxide was once used as an antiseptic on superficial wounds and injuries. It isn’t recommended for that purpose today. While it does kill bacteria, some studies have shown that it can be harmful to fibroblasts, which are cells your body needs for healing.

Medical opinions are mixed, but doctors at the Mayo Clinic now say we shouldn’t use it to clean cuts and wounds.

Don’t lighten your skin with it

Dermatologists might use hydrogen peroxide to treat some skin conditions, but it isn’t considered a safe way to lighten hyperpigmentation in at-home use. The risks outweigh any potential benefits, especially because there are other ways to lighten dark spots on your skin.

Don’t use it to treat acne

Yes, it bubbles and fizzes and kills bacteria, including the bacteria that can cause acne. But a 2005 study shows that hydrogen peroxide can also lead to scar formation, so using it directly on acne isn’t a good idea.

In general, it’s not a good idea to use hydrogen peroxide on your skin at all — even though there are plenty of websites that tout it as a health and beauty aid that can do anything from whitening your nails to softening calluses on your heels.

19. Do use it to sanitize your toothbrush and retainer

The American Dental Association says toothbrushes can be exposed to fecal coliform and other bacteria in the bathroom. Tiny amounts of these bacteria don’t usually cause health problems, but if you want to be on the safe side, soak your toothbrush in hydrogen peroxide.

A 2009 study found that rinsing in hydrogen peroxide reduced the bacterial count by 85 percent.

20. Do use it to sterilize makeup brushes

After washing excess makeup off your brushes with a gentle shampoo, soak the bristles for 10 minutes in a bowl of water with a teaspoon of 3 percent hydrogen peroxide. You can also use it to clean the pads on your eyelash curler. Rinse off any residue thoroughly to protect your eyes.

21. Do whiten your teeth

A bright smile is on just about everyone’s to-do list these days, and the market is teeming with products that use hydrogen peroxide to whiten teeth. Concentrations vary.

Some products available from dentists may contain 10 percent hydrogen peroxide. Studies show that these products are effective and safe when used properly.

22. Do consider letting a professional lighten your hair

Hydrogen peroxide is generally considered safe in commercial hair dyes, although research shows that serious chemical burns can happen, even in a professional salon.

Hair dyes with peroxide can damage your hair if you use them too often, so talk to a trained stylist to work out a schedule that’ll protect your hair and skin.

The familiar brown bottle contains 3 percent hydrogen peroxide, but there are much stronger concentrations on the market, including a 35 percent food grade hydrogen peroxide.

While food grade hydrogen peroxide has been discussed widely as a cure for conditions like cancer, lupus, and diabetes, these uses aren’t supported by science or doctors’ advice.

Don’t use hydrogen peroxide to treat or attempt to cure any of these conditions. Doing so could cause serious health problems and could even be fatal.

Hydrogen peroxide is a household chemical that can be safely used for a variety of cleaning purposes in your home. Although it was once commonly used to disinfect cuts and wounds, it isn’t recommended for that purpose today.

Hydrogen peroxide can reduce the likelihood that you’ll get sick if you use it to disinfect surfaces, produce, and other items in your home.

Don’t use it on your skin, don’t swallow it, and don’t try strong concentrations of food-grade hydrogen peroxide to try to cure illness. When used properly, hydrogen peroxide is still a helpful household disinfectant and health aid.