It's hard to believe that even today some people think washing a kid's mouth out with soap for sassing off is a good idea. The American Academy of Pediatrics considers it a form of child abuse.

But as recently as this year, a Florida teacher was suspended after she declared a talkative student needed to be punished like that, and proceeded to put hand sanitizer (the modern version) into his mouth.

In contrast, using mouthwash to rinse your mouth — voluntarily — can be a healthy step, according to a study in the Journal of Medical Virology. It knocks out the virus that causes COVID-19.

Researchers tested a wide range of mouthwashes, including Crest Pro Health (active ingredient cetylpyridium chloride; safe and effective, but shouldn't be used for more than seven days according to a 1994 FDA report) and Listerine Antiseptic (active ingredients eucalyptol, menthol, methyl salicylate, and thymol). They also looked at hydrogen peroxide–based mouthwashes.

They found that Crest Pro Health killed at least 99.9% of the virus in the mouth; Listerine Antiseptic killed more than 99.99%; and peroxide brands knocked out slightly less.

Overall, the researchers say, "Most of the common over-the-counter mouthwashes/gargles tested demonstrated at least a 90% reduction in infectious virus at one minute of contact time."

And the longer you rinse, the more power they have.

If you want to do all you can to keep COVID-19 at bay, mouthwash is one more effective technique to complement mask wearing and social distancing.