Washing your hands vigorously with soap and water for at least 20 seconds is the best defense against the spread of infectious diseases like coronavirus, according to the Centers for Disease Control and Prevention.

Second best is using a hand sanitizer, which is great for situations when you can't wash your hands. Unfortunately, many stores have sold out of sanitizer as fears about COVID-19 spread.

If you weren't able to buy a bottle at Target, Walmart or your favorite drug store, there's another option: Make your own.

Here are the ingredients:

—1/3 cup of aloe vera gel

—2/3 cup of 99% isopropyl alcohol (rubbing alcohol)

—Mixing bowl

—A spoon or whisk

—A clean, empty container, like a plastic travel bottle or a pump bottle.

Simply stir the aloe vera gel and alcohol until they are well blended and then decant the mixture into the bottle.

Optional: Add a few drops of your favorite essential oil while mixing. It won't have any effect on the potency of your concoction, but it might make it smell nicer.

That's all there is to it.

The most important thing, according to the CDC, is to make sure the alcohol content is at least 60 percent.

The CDC says sanitizer is only effective if you cover your hands thoroughly and then allow them to dry. Squirting a few drops into your palms and then wiping your hands won't help much.