Cleaning electronics
The one area where the risk is not what the liquid does to the surface, but where the liquid goes — and five manufacturers say the same thing about it.
What this area turns on
Usually the hazard of a cleaning liquid is chemical: what it does to the material it touches. On a powered device the dominant risk is POSITIONAL. The liquid may do nothing at all to the plastic it lands on and still destroy the device, because it did not stay there. Read that way, the manufacturer instructions stop being a fussy list and become one rule stated five times. Power off and disconnect first, so that anything which does get in is not energised when it arrives. Put the liquid on the cloth and NEVER on the product, because a spray goes where the nozzle points and also where it does not. Damp, not dripping. Nothing into the openings. And air dry completely before power is restored, which closes the loop back to the first instruction. Five independent makers — a computer maker, a phone maker, an optical manufacturer, an audio guide and a flooring guide — give that instruction in the same terms. On chemistry the guidance is narrower than people expect and more specific than they assume: over 70% isopropyl alcohol or ethanol is cleared by two device manufacturers on hard glass, ceramic and metal surfaces, while bleach, ammonia, hydrogen peroxide, window cleaner and a long list of solvents are prohibited by name. The gaps matter as much as the guidance. A phone maker's instructions stop at glass, ceramic and metal — so a rubber or leather case is outside it. Nobody publishes a charging-port procedure, and the same guidance prohibits the compressed air every consumer article recommends for exactly that job. And no manufacturer states whether alcohol is safe on a coated spectacle lens, which sits awkwardly beside a display the same chemical is cleared on.
Assessed and found wanting
Widely repeated techniques in this area that the evidence does not support, or supports only in part.
Following bleach with an alcohol sanitiser
Does not workDoing both to be thorough is the reasoning, and the two react. Hypochlorite with alcohols forms chloroform.
You will smell it if the fumes are dangerous
Does not workTwo regulator fact sheets carry the same explicit warning against exactly this assumption, and the gas people worry about most smells pleasant.
Its health rating is 1 and its flammability rating is 3. The hazard people underrate is the one the regulator rates highest.
Fabric softener is fine on everything
Does not workTwo manufacturers exclude it outright, for the same reason in different words: it leaves a deposit, and the deposit is the problem.
Spraying cleaner onto a screen or keyboard
Does not workEvery manufacturer instruction says the same thing: put the liquid on the cloth, never on the device. A spray goes where the nozzle points and also where it does not.
In this guide
Laptop computer
Thing to cleanAn object where the cleaning question and the electrical question are one and the same, and where the manufacturer's answer is mostly a list of things not to do.
Laptop keyboard
ComponentA horizontal grid of openings directly above the electronics. Every cleaning instruction for it is really an instruction about keeping liquid out.
Mobile phone
Thing to cleanThe most-handled object anyone owns, and the manufacturer's guidance stops at glass, ceramic and metal — which leaves the case and the charging port outside it.
Phone charging port
ComponentOne of the most-asked cleaning questions there is, and the manufacturer's guidance does not answer it — while prohibiting the tool every article recommends.
On an appliance the question is not what the liquid does to the surface but where the liquid goes. Every manufacturer instruction here is a containment instruction wearing cleaning clothes.
Coated spectacle lens
Material or surfaceA coated optical surface where the hazard is not the cleaner but the grit in whatever you wipe it with — and where a scratch is replaced rather than repaired.
Spectacles
Thing to cleanCleaned more often than anything else a person owns, almost always on a shirt tail, which is the one method the lens manufacturer names as damaging.
Isopropyl alcohol
Cleaning agentA solvent that dissolves oils and residues and evaporates without a trace. Useful on electronics and glass; flammable, and damaging to some plastics and finishes.
Microfibre cloth
EquipmentSplit synthetic fibres with a very large surface area, which lift and trap soil mechanically — often with water alone.
Blowing out a charging port with compressed air
Claim or techniqueThe most recommended technique for the most asked question, and the phone manufacturer prohibits it by name while publishing no alternative.
Spraying cleaner onto a screen or keyboard
Claim or techniqueEvery manufacturer instruction says the same thing: put the liquid on the cloth, never on the device. A spray goes where the nozzle points and also where it does not.