does putting a potato in soup really work to make it less salty?

yea it works really well, just place a peeled raw potato in and let it cook, continue to taste until it reaches your desired saltiness or unsaltiness rather

A lot of people will say it does. And I expect I'll get some flak, but there is no science that would explain how it could work. I suspect that it is an old wives tale (or in this case an old chefs tale). No, a potato will not remove the salt. It may dilute the soup though.

PhD Food Chemistry and Nutrition

Yes, I learned that from Martha Stewart. Potatoes absorb the excess salt.

Yes, and you can also try adding a few tablespoons of instant mashed potato flakes and stirring them in...

Yes it does. Also just remember for next time don't add any extra salt until you taste the soupf first.

it does, but you might want to set it in with a toothpick for easy removal.