Your Doorknobs Might Already Be Sterilizing Themselves—Here’s the Secret

published Feb 20, 2019
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(Image credit: Samara Vise)

Flu season may have peaked, but we’re not exactly off the hook. Staying vigilant with sanitizing and disinfecting around the home is key year-round to prevent the spread of illness. Your first line of defense? Stay on top of cleaning high-traffic spots like light switches and doorknobs, which are prime targets for bacteria and viruses—the likes of whom can hang out on hard surfaces for up to a week.

But before you restock your disinfectant arsenal, check out your hardware: While aluminum and stainless steel in particular are hotbeds for germs, studies show that brass, copper, and silver have self-sterilizing powers.

It’s not magic, it’s science. It’s called the oligodynamic effect.

How the Oligodynamic Effect Works

Basically, oligodynamic metals contain ions that destroy living cells, like bacteria, fungi, spores, and viruses. Remember studying affinities in high school biology? Interestingly, germs have an affinity for the metallic ions of silver, copper, and brass, which means the bad guys could be mostly gone in as little as 15 minutes. If you have unvarnished brass doorknobs or cabinet pulls, for instance, they’re naturally working around the clock to battle germs on your behalf.

(Image credit: Julia Steele)

There’s even more good news: It’s not just your doorknobs. The same self-sanitizing principle holds true for other items around your home, like copper pots and silver flatware. In one study, a copper pot killed salmonella microbes in drinking water within four hours, while silver did the same in about twice the time. Just keep in mind that most modern “silver” forks and spoons are actually steel, which unfortunately holds no magical germ-killing powers.

Moral of the story: If your door knobs disinfect themselves every 15 minutes, you could be cleaning them far less. But when sickness is rampant, go ahead and grab the sanitizer and practice good hand-washing, because it’s always better to be safe than sorry.