Why cleaning can do harm
A screen’s front surface is more delicate than it looks. Depending on the product, it may be glass, plastic or a film bonded to the panel, and it often carries one or more thin treatments: an anti-glare texture, an anti-reflective layer, an oil-repellent finish or a hard coating. These are covered in the article on anti-glare and glossy coatings. They are thin, and some wear off with rubbing or react badly to certain chemicals.
Once a coating is damaged, cleaning cannot restore it. A worn oil-repellent layer makes fingerprints stick more; a damaged anti-reflective layer shows up as patchy, cloudy areas. Cleaning that is meant to improve a screen can therefore make it look worse permanently. The safest approach is to do as little as is needed, and to start with the gentlest method.
First, check the maker’s guidance
The most reliable advice for a specific product is the one in its manual or on the maker’s support pages. Screens vary, and the instructions differ. Where the maker gives clear guidance, it overrides general advice. The principles below are common to many displays, but they are not a substitute for that guidance.
General principles
Switch off and unplug first. A dark, powered-off screen shows dust and smears more clearly, and it avoids any risk from moisture reaching live electronics. Let a screen that has been running cool down before cleaning.
Start dry. Dust and loose grit are the main cause of scratches, because rubbing grit across the surface drags it along like sandpaper. A soft, clean, dry, lint-free cloth, such as one made of microfiber, is a common choice. Wipe gently with light pressure. Avoid paper towels, tissues and rough fabrics, which can contain stiff fibers that scratch.
Use light pressure. Pressing hard is rarely necessary and can cause its own problems. On an LCD, pressure can temporarily distort the layers and leave a bright mark. Screens with a flexible surface, or touchscreens with soft layers, are especially sensitive to firm pressure.
Dampen the cloth, not the screen. If a dry wipe is not enough, lightly moisten the cloth with a small amount of water, or with whatever the maker recommends, and wipe. Do not spray liquid directly onto a display. Liquid can run to the edge and seep behind the front surface or into the frame, where it can cause staining, short circuits or corrosion. Even a little moisture trapped under the surface can leave marks that cannot be removed.
Wipe in one direction or in gentle strokes. Circular scrubbing tends to spread dirt around. Wipe softly, then use a clean, dry part of the cloth to remove leftover moisture.
Let it dry fully before turning it on. Do not close a laptop on a damp screen, as the moisture can transfer to the keyboard side and leave marks.
What to be careful with
Strong solvents. Alcohol, acetone, ammonia-based window cleaners, bleach and abrasive household cleaners are often listed as things to avoid. They can cloud or strip coatings, damage plastic and soften adhesives. Some makers do allow certain diluted alcohol-based wipes, while others do not, so it is another reason to check the manual first.
Disinfectants. Frequent sanitizing is common in shared spaces. Some products are made for use on electronics, and some makers publish guidance on what is acceptable. Repeated use of harsh disinfectants can wear coatings over time. Where cleaning is needed for hygiene reasons, such as in healthcare settings or on shared equipment, the maker’s guidance and the facility’s own rules should lead. The same applies in sensitive environments such as clinical display use.
Abrasive materials. Scouring pads, rough sponges and gritty cloths can scratch quickly. Even paper-based products can leave fine marks on soft surfaces.
Compressed air. It can blow dust off, but a strong blast near the edges can drive moisture or particles into gaps, and propellant liquid from a can held at the wrong angle can spray out. If you use it, short bursts at a distance are the sensible approach.
Fingernails and sharp tools. Trying to scrape off a stuck spot risks a scratch. Soften it with a damp cloth and gentle repeated wiping instead.
Cleaning the display while it is mounted tight. Pressing a screen against a wall mount can transfer force to the panel. Support it from behind with a free hand when wiping a wall-mounted unit.
Different screens, different needs
Phones and tablets. These get greasy from fingers, and many have oil-repellent layers that wear with cleaning. A soft cloth, lightly dampened if needed, is usually enough. The surface is in contact with skin and pockets, which is the main source of the dirt.
Computer monitors and TVs. These mostly collect dust and the odd fingerprint, so dry cleaning suffices most of the time. Matte surfaces may hold oils in their texture and can be harder to clean without leaving streaks.
Touchscreens in public use. Kiosks and shared panels are cleaned often and with stronger products. The coating and sealing should be designed for that, but the guidance for self-service kiosks and rugged enclosures shows that repeated cleaning is a design consideration, not something to assume is harmless. Touchscreens can also react to liquid on the surface, so cleaning on a powered screen can produce false touches.
Interactive boards and large panels. Large surfaces are cleaned in sections with a soft cloth. Interactive whiteboards may use pens or markers; the maker’s guidance on what to use for erasing and cleaning matters.
When something does go wrong
If liquid gets behind the screen, switch the device off, disconnect power, and do not use it until it is dry. Do not try to speed things up with heat. For scratches or coating loss, there is generally no cleaning fix; the options are to live with it or ask the maker or a service provider about repair, which is often limited because of the way screens are built, as explained under screen repairability.
The short version
Power off, dust off with a dry soft cloth, use a barely damp cloth if needed, and never spray liquid directly on the screen. Keep strong chemicals and rough materials away, and follow the maker’s instructions where they exist. Cleaning less often, and more gently, is usually better for the surface than cleaning thoroughly and frequently.