When it comes to how Americans use soap, it’s fair to say millennials are making a clean sweep of it.

Americans between 18 to 24 are largely snubbing the old-fashioned bar of soap, leading to sales declines for the likes of Ivory’s iconic 125-year old bar and its bar soap rivals, according to new data from consumer research firm Mintel. Consumers who still buy bar soap, it turns out, have something in common: they tend to be over 60 years old and are men.

It’s not as if Americans are less clean. Sales of soap, bath and shower products are on the rise, with overall market growth of 2.7 percent last year, Mintel found. Sales of bar soaps, though, slipped 2.2 percent from 2014 to 2015 as younger consumers and women snubbed the traditional bar in favor of liquid soap. So what’s driving the generational shift? Millennials believe bar soaps are covered in germs after they are used.

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Some older Americans might scoff at that belief, and there’s some research to back them up. A 1988 study found that people who washed with bar soaps contaminated with bacteria didn’t have a detectable level of of the bacteria on their hands. There are a few issues with that study, however. For one, it was backed by Dial soap, and secondly, it was published before the spread of newer pathogens like antibiotic-resistant MRSA emerged, which raises the stakes for having clean hands. (Some millennials might point out it was published before they were born.)

On the hand, some health authorities are now recommending a switch to liquid soap, with Minnesota’s Department of Health​ noting that germs can grow on bar soap and spread infections.

About 60 percent of Americans over the age of 65 believe it’s fine to wash their faces with a bar of soap, compared with only 33 percent of people between 25 to 34 years old.

Liquid soap has something else going for it: a convenience factor that allows packaged goods companies to sell new products at a higher price point. Companies ranging from Procter & Gamble to Unilever are constantly tweaking their products to develop new products to appeal to young consumers. It may be no surprise that liquid soaps and in-shower moisturizers have a much higher price tag than the traditional bar of soap.

“In order to turn sluggish sales around, new bar soap product launches could incorporate a wider variety of claims, especially for more luxury and premium bar soap offerings,” said Margie Nanninga, beauty analyst at Mintel, in a statement.