CNN  — 

Tired of washing your hands for 20 seconds each time? Fingers starting to prune or feel like sandpaper?

Please don’t stop.

The world is counting on you to help stop the spread of Covid-19, the deadly new disease caused by SARS-CoV-2, or severe acute respiratory syndrome coronavirus 2.

Take heart that while you’re scrubbing, you’re also killing off a host of other nasty bacteria and potentially lethal viruses that have plagued humans for centuries – including influenza and a number of different coronaviruses.

“There are four coronaviruses that circulate in humans regularly, almost every year,” said virologist Dr. John Williams, chief of the division of pediatric infectious diseases at the University of Pittsburgh Medical Center Children’s Hospital of Pittsburgh.

“And they mainly cause colds; in fact, they cause about a third of common colds. They don’t kill people,” he added.

Coronaviruses aren’t the only nasty parasites that succumb to a vigorous application of soap and water. Influenza – which kills millions around the world each year – and the human metapneumovirus, which causes a respiratory infection that can lead to pneumonia, also break down and die.

How did such a simple thing as soap and warm water – and alcohol-based sanitizers – obtain such power over these parasites?

The answer lies in their “skin” and your scrubbing technique.

What soap and warm water do

Under the microscope, coronaviruses appear to be covered with pointy spires, giving them the appearance of having a crown or “corona” – hence the name. Beneath the crown is the outer layer of the virus, which is made up of lipids, or what you and I would call fat.

Now imagine that coronavirus is your butter dish, covered with buttery fat.

“You try to wash your butter dish with water alone, but that butter is not coming off the dish,” Williams explained. “You need some soap to dissolve grease. So soap or alcohol are very, very effective against dissolving that greasy liquid coating of the virus.”

What does getting rid of that outer layer do to the germ?

“It physically inactivates the virus, so it can’t bind to and enter human cells anymore,” Wllliams said.

Just how soap accomplishes this feat is rather strange and fascinating science.

It’s all about how soap mol