I've never cleaned my mobile phone, but after chatting with experts for this story, it was the first thing I did.
It turns out mobile phones are "Trojan horses" for carrying germs. That's according to Lotti Tajouri, an associate professor in molecular biology and genomics at Bond University and Murdoch University.
He found more than 17,000 micro-organisms, including bacteria, viruses, fungi and parasites, living on 95 mobile phones he studied.
And with 80 per cent of people surveyed by Dr Tajouri admitting to using their phone in a public toilet, we can start to understand how they get there.
"Mobile phones behave like biological magnets," he says, adding their warm and moist conditions act like "five-star hotel accommodation for microorganisms".
If you're understandably grossed out, keep reading to find out the best way to clean your phone, and how often you need to be doing it.
What lives on our phone and is it harmful?
In the 95 phones Dr Tajouri and his team analysed, they also found super bugs (germs that are very hard to treat), antibiotic resistant genes, and virulence factor genes (these increase a pathogen's ability to cause disease).
He says micro-organisms thrive on phones because they are high-touch surfaces that deliver the right "breeding ground" conditions.
"We load them with all sorts of microbes through our fingers … and when we talk into them, we drop little droplets of saliva.
We transfer these germs back to our faces, Dr Tajouri says, by touching our lips, eyes and nose on average 25 times in an hour.
"Eighty per cent of common infections are associated with hands. Mobile phones negate handwashing."
Immunocompromised people are most at risk of illness from their phones, Dr Tajouri says.
"That includes infants, the elderly, and of course people with chronic disease like diabetes."
Meena Jha, head of technology at Central Queensland University, says while having germs on your phone doesn't "automatically make you sick", we do need to be practising good hand and surface hygiene.
"I wouldn't describe the phone as inherently dangerous. But it's about recognising it's a frequently touched surface that can catch microbes.
"We should be cleaning them, and we often forget."
Who is cleaning their phone anyway?
Not me (until recently), but I'm in good company.
According to Dr Tajouri's research, most participants never or rarely clean their devices.
For example, a survey he conducted with hospital staff in Queensland found 52 per cent admitted to using their mobile phones in the toilet, and 57 per cent said they never cleaned them.
How to clean your phone without damaging it
Before cleaning your phone, you need to unplug it (if it's being charged) and remove any protective cases and accessories, explains Dr Jha.
If you want to disinfect it, Dr Jha recommends no higher than 70 per cent isopropyl alcohol wipes, which is in line with most guidelines backed by major manufacturers.
"Use it gently, and the most important thing is to not spray anything directly onto the phone."
She says any cloths or wipes should be damp, not dripping wet, as you want to keep moisture away from charging ports and speakers.
For those areas, Dr Jha says you can use a soft, dry brush.
And avoid any strong cleaning products.
"Anything that can be harmful for your kitchen top — you should not be using that," Dr Jha says.
For example, she says vinegar, bleach and hydrogen peroxide are too aggressive for a smartphone's "oleophobic layer".
"That layer resists fingerprints and smudges. Harsh chemicals and excessive scrubbing will gradually strip this coating and reduce touch responsiveness."
Dr Jha recommends cleaning your phone once a week "but context matters".
If you are regularly taking your phone into a hospital setting, for example, you may like to clean more frequently.
Dr Jha warns against being "obsessive" about cleaning as it may damage the device.
Reducing germ risk and spread
Dr Tajouri is particularly passionate about people not using their phones in toilets to help reduce risk.
He says public toilets are often not cleaned frequently or well, "and we touch a lot of contaminated areas: faucets, flush button, doorknobs, toilet seat. Then we touch our phone."
"And when you flush, there is a plume effect."
Dr Tajouri says droplets from the toilet bowl can contain bacteria and viruses and travel up to 2 metres.
