If you read public health guidance on dealing with the many risks posed by the Coronavirus COVID-19, you’ll be aware of the importance of disinfecting surfaces which have come into contact with someone with the infection. This article looks more closely at what that entails, with respect to Macs and related devices.

The Coronavirus is very different from bacteria, which we’re most used to dealing with. The great majority of cleaning and disinfection products concentrate on their effectiveness again bacteria. This is because studies and experience with viruses are more limited, and many viruses are known to be quite fragile when outside living organisms. Thankfully, the Coronavirus turns out to be one of those fragile viruses, so it won’t live on in the soil like the bacteria which cause tetanus, for example. But it’s also extremely successful at being spread through the air, in aerosols and droplets, and on surfaces that we touch.

There’s also a big difference between cleaning and disinfecting. When a surface looks sparkling and ‘clean’, that’s been cleaned. Latest evidence, though, is that some of the surfaces we consider easiest to get to look clean, like stainless steel and plastics, can leave the Coronavirus alive for longer (see Further Reading below). Just because something looks cleaner than dirty doesn’t mean that it has been properly disinfected.

If the Coronavirus is going to die when left alone outside the body, why don’t we just leave surfaces alone and wait for that to happen? We can, and in many circumstances will do so, but that entails leaving possibly contaminated objects for several days, best at least a week, before anyone can touch them again. So in most circumstances, you’re going to want to disinfect things like keyboards, trackpads, mice, touchscreens, etc., rather than seal them away with big yellow-and-black warning signs attached.

Two common circumstances in which you’re going to consider disinfecting your Mac’s surfaces are when someone has been using it and then goes down with Coronavirus, and when you’ve had the infection yourself and are recovering. A much more difficult problem, which you should avoid if at all possible, is when someone with the infection needs to share keyboards and other items with someone who hasn’t had the infection.

In choosing a suitable disinfection agent, you need to know what Apple recommends as being safe with the materials it uses. There’s no point in disinfecting a keyboard with a substance which removes the markings on its keys; similarly, some disinfectants can remove or damage the coatings put on touchscreen and other displays.

As I have pointed out, Apple has recently changed its recommendations on what you can use to clean its hardware. In particular, this now permits the use of 70% isopropyl alcohol on hard and nonporous surfaces.

That refers to cleaning, not disinfecting, though. If you follow the link in that article to Apple’s guidance on disinfection, you’ll be taken to an old article which hasn’t been updated, and refers to two proprietary products, neither of which includes 70% isopropyl alcohol. Apple needs to issue fresh guidance on disinfecting its products as a matter of urgency, as a great many Mac and device users now need to know best recommendations.

What should you do, then?

First and foremost, follow expert public health guidance and recommendations. If you choose to do different, ensure that what you do is more, additional to that guidance, and no less effective. Don’t trust anything you see being suggested in social media: go to official recommendations.

If, as I suspect, you won’t find specific information there, consider using 70% isopropyl alcohol, as included in Apple’s latest recommendations. It’s inevitably in short supply and expensive, but stored properly (it’s flammable, toxic and a skin irritant) has a long shelf life. Don’t try washing keyboards in it, even if you’ve got ample, but wipe them down carefully and thoroughly until they’re properly clean. Dry the surfaces well, and leave them until they’re thoroughly dry before using again.

If you can’t or won’t use isopropyl alcohol, then following Apple’s suggestions for cleaning should be almost as good. The snag is that no one seems to know for sure how good any of these procedures are. So long as what you do doesn’t risk damaging the device, it’s almost certain to be better than doing nothing at all.

Although there’s no absolute guarantee that using isopropyl alcohol will remove or kill every virus from a keyboard/trackpad/mouse/etc., it will greatly reduce the risk of that surface being able to transmit the infection. Once disinfected, leaving the object without handling it for another few days may help ensure that any remaining virus dies.

Stay safe and healthy.

Further reading

Latest MIT research on the persistence of COVID-19 on different surfaces, with a link to the preprint.

Open source systematic review on contamination of peripherals. Although aimed at healthcare environments and technical in content, this gives a good idea of how little we know about this subject.