Anyone who has ever pounded the pavement in strappy sandals knows that, by dusk, your soles are the color of the asphalt you’ve been strolling. We won’t even get into the “tan line” of grime around your ankle strap.

After finding out what your feet have picked up—a seriously unappetizing stew of germs—you may be ready to ditch your Havaianas for a pair of knee-high boots.

“When walking on the street in something like a flip-flop, you are exposing your foot to vomitus, human waste, dog feces, sputum expectorated by people—some of whom may have microbacteria—and a wide variety of other things like food or liquids that have been brewing in the hot sun,” says Philip Tierno, Ph.D., director of clinical microbiology and immunology at New York University Langone Medical Center and author of “Secret Life of Germs.”

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The kind of cooties you find on city streets, he says, include norovirus (that scourge of cruise ship passengers), staph aureus, types of strep, E. coli and drug-resistant superbugs like Pseudomonas, Klebsiella pneumonia and MRSA. “The summer heat,” he adds, “acts like an incubator.”

If your feet have cuts or open blisters, you may unknowingly be laying out a welcome mat to the viruses and bacteria stuck to the street. But even if you’re abrasion-free, you can transfer all of that nasty stuff the moment you handle your flip-flops when you slip them off or drop them in your bag to change into heels.

Clean Your Skanky Flip Flops

The easiest way to clean your entire collection of flip-flops? Dump them in a washing machine with a small amount of detergent and/or an oxygen cleanser. Use the delicate setting and cool or warm water (not hot). If that doesn’t get rid of grime, try scrubbing your flip-flops with a discarded toothbrush and dish soap or slightly abrasive Arm & Hammer Baking Soda for sandals that practically sparkle.

Explains Tierno, “You’re exposed to something even worse—these organisms on your hands.” According to Dr. Tierno, 80 percent of all infectious diseases are transmitted by direct or indirect touching—kissing or picking up a dirty shoe—then touching your eyes, nose or mouth.

But before you reserve a spot in the nearest plastic bubble, there is good news. “Your skin is built to protect you from getting infected by its very nature,” says Jeannette Graf, M.D., assistant clinical professor of dermatology at Mount Sinai Medical Center in Manhattan. The dead skin layer known as the stratum corneum is thickest on the hands and feet and is considered your body’s first line of defense. “Our skin makes antimicrobial peptides that fight against bacteria and viruses and lots of different pathogens,” explains Dr. Graf.

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And there are several steps you can take to prevent your tootsies from transferring germs to your hands. Shoe designer Matt Bernson, whose creations are worn by actress Amanda Seyfried and model Gisele Bundchen, has a suggestion for the legions of women who swap out their shoes when they arrive at work or home: “Carry your shoes in a shoe bag when they are in your purse.”

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To banish germs, use good old-fashioned soap and water. “You want to wash your feet when you get home,” says Dr. Graf. Or in a pinch, apply an antibacterial hand sanitizer on your feet, she suggests. Also, park a pair of slippers by the front door. “In general, it’s not a good idea to come into your home with dirty shoes that have walked on every known substance and schmear it all over your house,” says Tierno.

You can help keep your skin’s protective barrier in peak condition by exfoliating dead skin cells and slathering on moisturizer, says Dr. Graf. Gently smooth rough spots and calluses with a foot file or pumice stone, such as Sally Hansen’s Prep your Pedi Foot File or Pumice Foot Polish—not with one of those callus razors, says Ji Baek, founder of and author of Rescue Your Nails. “They’re illegal in many states,” says Baek, and they can cut your foot way too deeply. “It’s better to use a foot file and liquid soap when you get home at night.”

Or try a homemade foot soak and scrub. Donna Perillo of Manhattan’s Sweet Lily Natural Nail Spa adds warm citrus juice (grapefruit or orange) to a foot soak. “The acidity kind of eats at the grime,” she says. Follow that up with an all-natural sugar scrub, which you can make at home using granulated sugar, olive oil and your favorite essential oil. And then apply moisturizer.

Dr. Graf recommends using a lotion with skin-smoothing lactic or salicylic acid or urea before bed each night. Or you can lightly coat your feet with Vaseline petroleum jelly and then slip on cotton socks, such as Moisture Jamzz socks to protect your sheets. You’ll wake up with super-soft, germ-free feet.

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