It's been part of my job for several decades to handle things that other people have handled. Not only do I repair tech gadgets like smartphones and PCs, but I also dabble with automotive repair, and I'm here to tell you that people are disgusting. Not deliberately disgusting, I just think that it's something in our human nature where we become relaxed around our own bodily secretions.
I've seen things that I cannot unsee.
Keyboards with food and hair and toenails jammed under the keys. Smartphones are covered in all kinds of greasy schmoo. PCs filled with strange and weird filth. Mice filled with more hair than you'll find on a real mouse. Screens and displays covered with boogers and, I'm sorry to say, much worse.
Now, if it's your keyboard or mouse or screen or smartphone, it's your schmoo and secretions and germs you're touching.
But that doesn't mean that I want to be touching it.
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Many years ago, I put together an IT tech repair toolkit, and one of the things that I put on the list was hand sanitizer. I wasn't joking. I know where people's paws have been before pawing their devices.
While washing your hands with soap and hot water for at least 20 seconds is the best way to combat nasties that might mean us harm, it's not always convenient. This is why I use hand sanitizer between bathroom breaks.
I've been using commercial benzalkonium chloride mousse sanitizers for years, but have also made my own from lab-grade 50 percent benzalkonium chloride (known as BAC 50) diluted down to 0.2 percent. However, unless you're comfortable handling chemicals that can, in their undiluted form, cause skin burns, I don't recommend this and suggest you stick to the commercially available stuff.
While benzalkonium chloride is less effective against nasties than some of the alternatives, I prefer it over alcohol-based sanitizers because I've come across plastics and rubbers that are not happy with alcohol exposure (for example, alcohol can make keyboard lettering vanish).
As for gloves, I don't wear them as often as I should. If I'm handling something particularly nasty (or doing automotive repair), then I'll don a pair of disposable nitrile gloves. These are naturally antistatic, which makes them great for working with delicate components.
I also try to not touch my face, but I'll tell you now that this is much easier to type than it is to do in reality. In fact, I'm touching my face right now.
And I'm pretty sure you are touching your face right now too.
As for cleaning devices and surfaces, there are lots of suggestions here on how to do that. I tend to use microfiber cloths on other people's gear because using liquids could have downsides (or it might end up being blamed for something). I'll also use canned compressed air (outdoors, wearing eye protection -- because toenails are sharp -- and wearing an N95 mask) to remove big chunks of detritus.
I don't want to make anyone paranoid, but when cold and flu and coronavirus come calling, touching anything that other people have handled recently -- iPhones, keyboards, door handles -- can be problematic, and the best defense is to be responsible for your own actions. Wash your hands regularly, and keep them out of your eyes and nose and mouth. Wear gloves if that makes you more aware of touching your face. Work on containing your coughs and sneezes, and be mindful of the biological and virological you are leaving in your wake.