Ways You’re Washing Your Hands Wrong

And you thought you mastered hand-washing as a kid.

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That means any germs you pick up in the bathroom can linger and potentially spread if you touch another porous area, particularly your mouth—not to mention they can get passed to another person who comes in contact with your dirty hands. Consider this: The average person touches his or her face 16 times an hour, says Charles Gerba, PhD, a microbiologist at the University of Arizona.

If you don’t already, you should also wash your hands before eating or preparing a meal, so the food doesn’t get contaminated either (hello, food poisoning!).

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quicklist: 2category: Ways You’re Washing Your Hands Wrongtitle: You don’t use soapurl:text:Soap does a lot more than make your hands smell nice. Soap is a chemical concoction made specifically for lifting sticky bugs off your skin. Since the surfaces of bacteria and viruses are made partly of fatty materials, ingredients in soap create a chemical reaction that grabs onto the germs so they rinse right off with the lather, Dr. Marty says.

Another thing to keep in mind: Liquid soap tends to be more effective than bar soap because it’s less likely to be contaminated, Dr. Marty says.

quicklist: 3category: Ways You’re Washing Your Hands Wrongtitle: You don’t scrub long enoughurl:text:Soap won’t help if you rinse it off immediately. You need to scrub for at least 20 to 30 seconds, long enough to hum “Happy Birthday” twice. Use that time to rub both your palms, the backs of your hands, and between your fingers. Place one hand on top of the other and scrub with your fingers interlaced, then switch. That way you’ll cover all sides of both sets of fingers.

One overlooked spot: your fingernails. “A lot of bacteria and viruses can get trapped there,” Dr. Marty says. To clean underneath your nails, take your right hand and rub the tips of your fingers on the palm of your left hand and vice versa.

quicklist: 4category: Ways You’re Washing Your Hands Wrongtitle: You always use hand dryersurl:text:“Studies show you’re better off using paper towels,” Dr. Marty says. The main problem is that people just don’t use hand dryers for long enough for their hands to dry fully—the CDC recommends 30 to 45 seconds—and wet hands spread bacteria more readily than dry hands. Plus, recent research suggests that when people wash their hands poorly, hand dryers may then propel the germs from their hands around the bathroom, making the restroom a grosser place for everyone.

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quicklist: 5category: Ways You’re Washing Your Hands Wrongtitle: You touch things right after washingurl:text:You put so much effort into washing your hands, don’t mess it up by touching a grimy spot before you even exit the bathroom (remember, 10% of bathroom-goers don’t bother to wash their hands, which means their germs are everywhere). Use a paper towel to turn off the water and a different one to dry your hands. Finally, grab another paper towel to take with you so you can use it as a barrier between your hand and the door before tossing it.

This article originally appeared on Health.com.