Old-fashioned bristle shaving brushes—so manly, so nostalgic, so evocative of suspenders on strapping shoulders. Aside from everything else that’s wrong with such historical stereotyping, there’s also the fact that those brushes apparently gave a lot of men anthrax on their face in the 1920s.

The Verge points to some historical detective work by the CDC.

During World War I, anthrax cases started cropping up in the US and UK. At first, officials with the British armed forces thought that the anthrax infections of soldiers’ heads and necks were because of “diabolical tactics of the enemy.” But contemporary researchers were eventually able to track the outbreak back to the shaving brushes provided to the soldiers. (Chemical weapons employed during WWI meant soldiers had to wear gas masks — and gas masks were thought to fit better on clean-shaven faces.)

You see, anthrax spores can get into your skin via a cut, potentially causing “swelling, itchy bumps or blisters, and also painless ulcers with a black center.” It’s not the most dangerous way to tangle with anthrax, but untreated it could kill one in five people. And all of World War I conspired to spread it:

The contaminated brushes were also, for the most part, counterfeit. When World War I cut off the regular supply of badger hair from Russia, the market opened up for knockoff badger hair — which was really horsehair from Russia, China, and Japan. Apparently, horses and other herbivores are more at risk for anthrax infections than badgers and pigs, which are omnivores. And while the real bundles of badger hair had been disinfected before they reached the US, these knockoff horsehair bundles weren’t.

Anything made after about 1930, including modern versions, is likely fine. Just don’t get so into your Edison bulb/pickle barrel/reclaimed wood nonsense that you willfully ignore your rightful suspicion that you should probably steer clear of antiques so intimate.