Dr. Sanjay Gupta gives a handwashing tutorial explaining why what you do for the full 20 seconds important, but he says it’s what you do when you’re finished that’s just as critical.

• Step 1: Dr. Sanjay Gupta says to wet your hands first and then put plenty of soap on them.
• Step 2: Rub your hands thoroughly, not under the water, making sure to interlace your fingers and continue rubbing. Then, interlace your fingers on the other side. “Make sure to get the backs of your hands. People often forget that,” said Gupta.
• Step 3: Get underneath the finger tips and the finger nails.
• Step 4: Get the thumbs. Dr. Gupta says the thumbs are really important. Rub them clean.
• Final step: Rinse the soap off. Then, what Dr. Gupta says is the key: Don’t turn the water off until you’ve dried your hands. Make sure to do it with the towel or paper towel. You don’t want to touch the dirty faucet handle with clean hands and contaminate them.

The CDC says you should wash your hands frequently. Soap and water is the best defense. If you use hand sanitizer, use one which contains at least 60% alcohol. However, while hand sanitizer can reduce germs on your hands, it doesn’t get rid of all types of germs. So use soap and water if you have a choice.