Sticky keys, crumbs wedged into the gaps, all covered in a sprinkling of dust – just flipping your keyboard upside down is enough to see how much dirt is crammed in there.
As the spread of the novel coronavirus makes us more and more aware of our hygiene habits, it's time to learn the best ways to go about making your computer's surfaces a bit less of a health hazard.
While health authorities have initially pointed to coughs and sneezes being the main sources of transmission, the World Health Organization says the virus may be also able to survive on certain surfaces for a few hours or up to several days.
"If you think a surface may be infected, clean it with simple disinfectant to kill the virus and protect yourself and others," the WHO recommends. However manufacturers have warned that disinfectant and cleaning agents can be damaging to certain parts of devices.
Keyboards: Shake, brush and blow
To clean a keyboard, first turn the computer off so you're notting hitting any keys, then flip the keyboard upside down and give it a few careful taps. You'll be surprised how many crumbs will fall out.
Follow this up with a soft brush to get deeper between the keys, or use a compressed air spray can to blow dust out of the cracks. But don't be tempted to use a domestic vacuum cleaner. "These are usually much too strong and could loosen the keys or damage the contacts," says hardware specialist Rainer Schuldt.
Encrustations, superficial yellowing and flakes of skin can usually be removed with a slightly damp all-purpose cloth. There are also special types of putty available that you press onto the keyboard to clean and disinfect keys.
Cleaning keys in the dishwasher?
Standard methods of cleaning might not be enough if the keyboard is very dirty. If so, the keys of mechanical keyboards can be removed individually and cleaned in the cutlery basket of a dishwasher, computer specialist Andreas Hentschel says.
It's a good idea to securely close the basket, preferably with a piece of wire or a paper clip, so that the keys do not fly around in the machine during the wash cycle.
A spin-free washing machine cycle at 30°C is a good alternative, but not with any items of laundry from which the colour might run. It's best to put the keys in a washing bag. Once the cycle is over, dry them thoroughly on kitchen paper to absorb the moisture.
A useful tip is to take a picture of the keyboard before you start, so that you can put all the clean keys back in the right place.
Screens: No need for expensive cleaners
Special cloths and cleaning agents for computer monitors are quite expensive – and are actually unnecessary. A normal, lint-free cloth will be enough to remove streaks, dust and fingerprints from a screen.
"Don't use paper tissues because they often contain wood, which scratches the displays," says computer expert Ulrike Kuhlmann.
Under no circumstances should you use a sponge or a cloth with a rough surface, warns Andreas Hentschel. "With the foils and plastics used on displays, they're only going to cause damage," he says.
For smartphone screens, Apple warns iPhone owners to avoid compressed air and cleaning products, as these may damage the outer coating and scratch the phone. Smartphone manufacturers instead recommend a slightly damp, lint-free cloth.
Disinfectants, while an effective way to kill germs off a phone, will damage the outer glass coating that prevents fingerprint marks, meaning these are better kept to non-glass surfaces on your devices.
Alternatively, ultraviolet light has been shown to kill germs off smartphone surfaces without causing damage, and UV phone baths are increasingly available in gadgets shops and online.
However Ulrike Kuhlmann suggests simply using warm water with some washing-up liquid. Dip the cloth into it and wring it out thoroughly. She recommends wiping computer and smartphone screens very carefully without pressing too hard, and to always work from the outside towards the centre, otherwise dirt will be pressed under the edge of the screen. – dpa