We know you can’t wait to rush home from the flea market to bust out that newly acquired antique shaving brush, and put it to use getting rid of your wintry fur. But before you lather up with your historically accurate brush, be aware that there’s a chance it may be carrying some era-appropriate anthrax.

Scientists at the Centers for Disease Control and Prevention published an article [PDF] in the current issue of Emerging Infectious Diseases that looked at outbreaks of anthrax infections of the skin in the early 20th century, which may be linked to poorly disinfected animal hair shaving brushes.

Wartime cut off Russian exports of badger hair — which was prized for shaving brushes due to its ability to hold water — prompting manufacturers to pass off cheap brushes made from imported horsehair as the real thing.

Some were not effectively disinfected, however, and ended up carrying Bacillus anthracis, which could easily sneak into the skin through any tiny nicks and cuts made by a razor.

“Public health officials investigating these outbreaks at the time speculated that at least some of these manufacturers used the hair as received, assuming it was already disinfected,” researchers note.

Before the war, bundles of hair used to make the shaving brushes were all cleaned and disinfected in Europe before heading to the U.S. During the war, those bundles were shipped straight to the U.S., some of them bringing anthrax with them.

Health officials eventually caught on, and enacted a series of control measures to keep anthrax out of grooming products, including a 1918 Surgeon General report publicizing a method for disinfecting brush hair, followed by “a slew of edicts” in 1920 by the New York City Board of Health.

Scientists want to bring this up again now because, well, hipsters:

“This historical information is relevant to current public health practice because renewed interest in vintage and animal-hair shaving brushes has been seen in popular culture,” the scientists write.

There’s been a resurgence of interest in luxury-brand, animal-hair shaving brushes — “evocative of an idyllic premodern esthetic” — researchers say, noting that a spring 2017 Google search for “badger shaving brush shopping” produced about 1.8 million hits.

And while scientists say that although the risk of acquiring anthrax from a shaving brush has been low since the mid-1920s, “those interested in a return to natural grooming” should know that using untreated hair from horses, pigs, badgers, or other animals poses “a potential, and perhaps hypothetical, risk of inoculating anthrax spores into the abrasions and minor lacerations caused by shaving razors.”

Modern decontamination and import regulations mean that new animal-hair brushes are unlikely to be a source of anthrax, researchers say, but if you want to be authentic and avoid anthrax, look for brushes manufactured in the United States after 1930.

The risk from “well-used (even vintage) brushes would seem to be extremely low,” scientists add, so if your Great-Grandpa used it every day without getting anthrax in his skin it should be okay.

Don’t try to disinfect your old brush at home, however.

“We do not recommend trying to disinfect vintage brushes at home because the risks associated with various combinations of steam, pressure, and formaldehyde are likely to outweigh possible benefits,” researchers note.

[h/t The Verge]