This science-backed trick is a throwback from 2011—but it’s really coming in handy right now.

By Maggie Seaver
April 24, 2020
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You know what’s not fun? Wearing a face mask to help slow the spread of COVID-19 like a responsible citizen, and then being rewarded with totally fogged-up glasses. Yes, we’d rather get foggy glasses than catch or spread this unprecedented virus—or go against CDC recommendations to wear a face covering in public—but it’s still a nuisance.

In fact, medical professionals (and many others) have dealt with inconvenient, face-mask-induced spectacle condensation on the job for far longer than the rest of us have since trying to quell this pandemic. Sure, getting foggy glasses from your DIY bandana mask might make for a funny selfie, but imagine trying to navigate a hospital with vapor-obstructed glasses—as if life isn’t crazy enough for healthcare workers already.

That’s why, back in 2011, two scientists published a study in the Annals of The Royal College of Surgeons of England that illuminates a super simple, at-home hack for this very phenomenon, which “can be a nuisance and even incapacitate” medical staff. Anti-fogging spray products do exist, but this trick requires zero shopping and adds no risk of putting harsh chemicals near the sensitive eye area.

Here’s how it works: Right before putting on a face mask to head to the grocery store, hit the pharmacy, or scrub in for surgery: “[W]ash the spectacles with soapy water and shake off the excess. Then, let the spectacles air dry or gently dry off the lenses with a soft tissue before putting them back on. Now the spectacle lenses should not mist up when the face mask is worn.”

How simple is that? But it’s scientifically sound, promise. As study authors Sheraz Shafi Malik and Shahbaz Shafi Malik explain, wearing a face mask directs warmer, exhaled breath upward (rather than outward, like normal) where your glasses sit. The warm water vapor condensing on the cooler surface of the lenses causes them to form tiny water droplets and get misty. “The droplets form because of the inherent surface tension between the water molecules.”

The soapy water’s sneaky role, then, is to leave behind an undetectable surfactant film that reduces said surface tension and allows these water molecules “to spread evenly into a transparent layer.” The authors also note this unassuming trick, or “surfactant effect,” can be used in any day-to-day attempt to prevent fogged-up glass surfaces. The more you know!

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This Story Originally Appeared On realsimple