Screen cleaning solutions are sold with a great deal of language about advanced formulations. The useful version is much shorter: a good one is purified water with a small amount of a mild surfactant, and possibly a trace of something to stop it going off in the bottle. That is the product.
Why water alone is not quite enough
Fingerprints are mostly oil, and oil and water do not mix. A surfactant is a molecule with a water-loving end and an oil-loving end, which lets the oil lift away with the water instead of smearing. That is the entire chemistry, and the amount needed is small — a solution that foams noticeably has too much of it and will leave a film.
Purified or distilled water matters for a mundane reason: tap water carries dissolved minerals that stay behind as spots when the water evaporates.
What does the damage
- Isopropyl alcohol and methylated spirits. Excellent degreasers that strip the oleophobic coating on phone glass. Once that coating is gone it does not come back, and the screen holds fingerprints permanently after.
- Ammonia, the active ingredient in most window cleaners. Same problem, plus it can attack plastic bezels and anti-glare films.
- Vinegar. A popular home remedy and mildly acidic, which is precisely what a coated surface does not need.
- Anything abrasive. Bicarbonate of soda paste appears in online guides. It is a mild abrasive. On glass with a coating a few molecules thick, mild is enough.
The cloth matters as much as the liquid
Microfibre works by trapping particles in the fibre structure rather than pushing them around. Paper towel and tissue are wood pulp and act as a very fine sandpaper. Wash the cloth every few weeks at 30 degrees with no fabric softener — softener coats the fibres and turns a good cloth into a smearing one.
Method, in five lines
- Turn the screen off so you can see the marks.
- Spray the cloth, never the device. Liquid at the edge of a screen finds its way inside.
- Wipe in straight passes rather than circles.
- Finish with a dry section of the cloth.
- Do not use any of this on an e-ink reader or a matte laptop panel without checking the manufacturer's advice.
About the kit sold here
It is 100 ml of alcohol-free, ammonia-free solution and one microfibre cloth, for $13.90 AUD posted from Newcastle. It is not a proprietary formulation and we do not claim it is: it is the ordinary correct thing for coated glass, in a bottle small enough to live in a bag. If you already own a decent cloth and a bottle that lists no alcohol, you do not need it, and this article has done its job either way.