Washing your hands often during cold and flu season is common sense. How to dry them is not.

Recent findings from the Mayo Clinic refute the popular belief that the air blowers found in most public restrooms are more hygienic than good ol' fashioned paper towels.

Even though the dryers are hands-free, paper towels are faster and less likely to spread germs.

"The trouble with blowers is they take so long," Rodney Lee Thompson, a hospital epidemiologist at the Mayo Clinic, told the Wall Street Journal. "Most people dry their hands for a bit, then wipe them on their dirty jeans, or open the door with their still-wet hands."

Or worse, because the dryers are noisy and time-consuming, some people skip hand-washing altogether.

The findings come at an important time. The flu season in the United States got off to its earliest start in nearly 10 years and is expected to be a bad one.

According to the Centers for Disease Control and Prevention, one of the best ways to keep the virus from spreading is to properly wash hands. It recommends washing your hands for about 20 seconds, or long enough to sing the entire "Happy Birthday" song twice. When your hands are all lathered up, make sure to rub all surfaces of both hands. Germs can hide under nails, too, so work in a nail brush if you have long nails. Dry hands completely to stave off bacteria.

Since only two out of three adults wash their hands after using the bathroom, Thompson also suggests opening the bathroom door with a paper towel, then tossing it over your shoulder and into the trash.

Can't do that with a hand dryer.