Picking your nose is unsightly, but who knew it can be lethal, too? A study by researchers at the Liverpool School of Tropical Medicine and Royal Liverpool Hospital have found that the habit can transfer bacteria that causes pneumonia. Blowing your nose, while more polite, is not any better for you, says Simon Gane, consultant rhinologist and surgeon with the Royal National Throat, Nose and Ear Hospital in London. “It might make it temporarily clear, but if you have a cold or allergies, a lot of the blocking is not from snot but from swelling of the lining. So, blowing it out won’t really help.”

Swallowing is a better way to go, says Gane. “You don’t even have to sniff and swallow; we naturally drain about two litres of snot and saliva from our nose, mouth and sinuses every day. Which is probably what the [stomach] acid is for – at least partially.”

Using topical decongestant sprays will alleviate nasal swelling slightly, but Gane advises that they should only be used for a couple of days as they can harm the lining of your nose. Your body has had millions of years of evolution to figure out what it’s doing, and if your nose is blocked, it’s blocked for a good reason. If it’s a temporary blockage brought on by a virus or allergies, the best thing to do is allow your body to handle it.

If you must blow, then do it gently and with one nostril. The lining inside your nose is very thin and doesn’t have a waterproof layer. “There are blood vessels close to the surface; increasing the pressure and irritating that can cause a nosebleed,” says Gane.

Use tissues instead of hankies. The NHS advises that you “Catch it, bin it, kill it” – and don’t forget to wash your hands afterwards.

If you don’t have a cold and just need to excavate unyielding bogeys, there are other ways of handling this than shoving your finger up there. “It’s probably better to wash them out with a salt-water wash,” Gane says. “You can buy sprays over the counter and clean more gently with that.”