Modern phone glass has a factory coating on it — an oleophobic layer, a few molecules thick, whose entire job is to stop fingerprints bonding to the surface. It is the reason a new phone wipes clean on a sleeve and a three-year-old phone does not. That coating is also the first thing to go, and most of the damage is self-inflicted.
What wears the coating off
Three things, in order of severity. Alcohol-based cleaners, which strip it directly. Abrasive cloth — paper towel, tissue, the corner of a jumper — which sands it away a little at a time. And grit: a phone that goes in a pocket with keys and sand picks up particles that a wipe then drags across the glass.
Sugar and butter, the actual hazards of an evening spent playing a bakery puzzle with biscuits, are harmless to the coating themselves. They just smear, and smears on a busy board are the reason you stop being able to see the difference between a red sweet and an orange one.
The correct method, which is dull
- Turn the screen off. Marks are invisible against a bright board and obvious against black glass.
- Wipe dry first with a clean microfibre cloth, in straight passes rather than circles, to lift the grit before anything wet is involved.
- If something is stuck on, dampen a corner of the cloth with plain water — not the screen — and go over that spot only.
- Finish with the dry part of the cloth.
- Wash the cloth every few weeks at 30°C with no fabric softener. Softener coats the fibres and turns a microfibre cloth into a smear machine.
What to keep away from it
- Window cleaner, ammonia, methylated spirits and neat isopropyl alcohol. All strip the coating.
- Paper towel and tissues. They are wood pulp; the glass wins, the coating does not.
- Compressed air aimed at speaker grilles, which pushes dust further in.
- Disinfectant wipes used daily. Occasional use of the wipes phone makers now approve is fine; daily use is not.
Once the coating has gone
It does not come back. A screen protector is the practical answer, and a cheap one will pick up fingerprints the same way an old screen does, so it is worth paying for one that lists an oleophobic layer in its own description. Re-coating kits exist and are, in our experience, a way to spend twenty dollars on a slightly greasier phone.
Why we ended up making a cloth
Because the cloth that comes with a pair of glasses is too small, hotel-style tissue is the wrong material, and the good ones are usually sold one at a time in a bag for six dollars. A five-pack means there is one in the bag, one at the desk, one in the kitchen and two in the wash, which is the only arrangement that actually keeps a screen clean.
Ours are 15 × 15 cm, lint-free and washable, $14.50 AUD for five, posted from Melbourne. There is no checkout — send the form and you will get an email with the total and postage.