Not by dropping them. Not by the case. By lifting them off a desk, breathing on the lenses and wiping with whatever is to hand.
The fix takes about twenty seconds and one habit, and the habit is the part most guides skip.
The one rule that prevents almost all of it
Rinse before you wipe. Every time.
The dust on your lenses is not soft. It is mostly mineral grit, fine sand and skin cells, and on a lens surface it behaves like very fine sandpaper. When you wipe a dry lens you are not removing that grit, you are dragging it across the coating under pressure.
A microfibre cloth does not save you here. A perfectly clean cloth pressing a grain of grit into a lens scratches the lens. The cloth is not the problem; the grit is, and the only way to remove grit without dragging it is to float it off with water.
That is the whole principle. Everything below is detail.
The twenty second method
- Run them under lukewarm tap water. Not hot. Let the water carry the dust off rather than scrubbing it off.
- One drop of plain washing-up liquid on your fingertips, and work it gently over both sides of each lens, the nose pads and the hinges. Use your fingers, not a cloth.
- Rinse thoroughly. Any soap left behind dries into a film you will then be tempted to wipe off dry, which puts you back where you started.
- Shake off the worst of the water, then blot dry with a clean microfibre cloth. Blot, do not scrub.
- Only now, if there are smears left, wipe gently in small circles with the dry part of the cloth.
Done daily this takes less time than hunting for a lens wipe.
What actually damages lenses
Modern lenses are plastic with coatings on top: anti-reflective, scratch resistant, sometimes blue light filtering or a mirror finish. The plastic is fairly tough. The coatings are what you are protecting, and they are what the following things destroy.
Ammonia based glass cleaner. The blue spray under most kitchen sinks. Excellent on windows, and it degrades anti-reflective coatings, which is why lenses cleaned with it develop a hazy, crazed look that no amount of polishing removes.
Alcohol, in quantity. Some coatings tolerate the occasional alcohol wipe, others cloud. Unless the lens manufacturer says otherwise, water and soap does the same job without the risk.
Vinegar, bleach, acetone, nail polish remover. All of them attack either the coating or the frame, and acetone will fog acetate.
Paper of any kind. Kitchen roll, tissues, napkins, toilet paper. Paper is wood fiber, and under magnification it is coarse and full of hard fragments. It is the single most common cause of the fine web of scratches people notice after a year.
Your shirt. Cotton and polyester are not the issue. The issue is that your shirt has been collecting grit all day, and you are now applying that grit to a dry lens with your thumb behind it for pressure.
Heat. Do not put glasses in a dishwasher, do not leave them on a car dashboard, and do not use hot water. Coatings and lens material expand at different rates, and the coating cracks first. That is what crazing is.
Saliva. It contains enzymes and bacteria, it leaves a film, and on a scratched lens it is a genuinely unpleasant idea. Breath is fine in an emergency; spit is not.
Microfibre cloths: the thing nobody mentions
A microfibre cloth works by trapping particles in the weave. That means a cloth that has done its job is now full of the grit it collected, and using it again presses that grit back into the lens.
- Wash it. By hand with a little soap, or in a machine in a laundry bag. Every week or two.
- No fabric softener. It coats the fibers and kills the electrostatic effect that makes microfibre work, leaving you with a smearing cloth.
- Air dry it. A tumble dryer melts the fibers.
- Do not keep it loose in a bag or pocket, where it collects exactly the debris you are trying to avoid.
If a cloth has been living at the bottom of a handbag for six months, it is not a cleaning cloth any more.
Cleaning the frame, not just the lenses
The parts people skip are the parts that actually get dirty.
Nose pads. Silicone pads collect skin oil and makeup and go yellow and slippery. A slippery pad is one of the quiet causes of a frame that will not stay up. Clean them with soap and your fingertip; on metal frames the pads can be replaced by an optician for very little.
Hinges. Grit in a hinge is what makes a frame feel loose, because it wears the metal every time you open it. Rinse and let the water do the work, then dry.
Where the arms meet your ears. The point of most contact with skin, and the point people never touch.
Acetate frames can be washed like the lenses, warm water and soap. Metal frames are the same, but dry them properly, because water sitting in a hinge or around a screw is how plating starts to lift.
Things that look like solutions and are not
Scratch removal kits. They work by abrading the lens surface, which means they remove the coating along with the scratch. The scratch becomes less visible and the lens is now unprotected and will haze. Scratches on a coated lens cannot be repaired. They can only be replaced.
Toothpaste. The internet's favorite remedy. It is a mild abrasive, which is exactly what you have spent this article avoiding.
Ultrasonic cleaners. Genuinely good for a dirty frame, and worth having if you wear glasses daily. Two cautions: use plain water or the fluid the maker specifies, and take stone-set or rhinestone frames out of the equation, because the vibration can loosen the settings.
Lens wipes. Convenient, and fine occasionally, but most are alcohol based and most people use them on a dry, dusty lens, which is the original problem in a sachet. Use them for a smear on a clean lens, not for actual dirt.
Which microfiber cloth for glasses
Any microfiber cloth for glasses works if it is clean, but the cloths sold for lenses are not all the same. The best eyeglass cleaning cloth is a tight, flat weave rather than the fluffy towel type, because a flat weave releases grit in the wash and leaves no lint on the lens. Size matters more than brand: a cloth big enough to fold twice gives you a fresh, dry face each time. Keep two in rotation, one in the case and one in the wash, and retire a cloth once it stops lifting a smear in one pass. The cloth that ships with a new frame is fine; the one that has lived in a pocket for months is not.
How to clean sunglasses
How to clean sunglasses is the same method with two additions. The coatings on a sun lens, the mirror finish and the polarising film in particular, sit on the outside of the lens and scratch the same way, so the rinse before you wipe rule matters more, not less; a mirror coating shows a swirl of fine scratches that a clear lens hides. And sunglasses collect sunscreen, which is an oil that water alone will not lift: use the drop of soap every time, work it into the rim where the lens meets the frame, and rinse until the surface no longer beads. Dry the frame as well as the lens, especially acetate and clear frames, which dull and yellow where sunscreen is left on them; the clear frame glasses guide covers that. Store sunglasses in a case rather than on a car dashboard, where heat crazes a coating faster than anything you do with a cloth.
Storage, which is half of it
A lens gets scratched when it touches something, and most of that contact happens when the glasses are not being worn.
- Case, closed, every time. Not the desk, not the car seat, not on top of your head.
- Fold the left arm first on most frames, which is the way the hinges were designed to sit.
- If you must set them down bare, lay them arms-open and lenses up. Face down on a hard surface is the single fastest way to scratch a lens.
- Keep them out of heat. A closed car in summer is well above anything a coating is designed for.
Coated lenses that change with the light need the same care as any other coated lens; the photochromic lenses guide explains what the coating does and why heat and age change how far it darkens.
Most of this routine exists to protect the coating; the anti reflective coating guide explains what the layers are.
Three related guides: the microfiber cloth guide covers how to wash the cloth and when to replace it, the scratched glasses guide explains why a dry wipe scratch cannot be repaired, and the night driving glasses guide shows why clean lenses matter most after dark.
The same soap and water wash is also the home fix for fog: a trace of dish soap left on the lens spreads condensation into a clear sheet, which the how to keep glasses from fogging up guide explains along with the mask fix and what never to use.
When to stop cleaning and see an optician
- The lens is hazy or crazed rather than dirty, which means the coating has gone and cleaning will not bring it back.
- The frame no longer sits level, which is an adjustment rather than a cleaning problem.
- A screw is loose; the how to tighten glasses guide shows the fix. Tighten it soon or lose it, and a lost screw on a metal frame usually means a lost lens.
- Nose pads have gone hard, yellow or slippery. They are a consumable and they are cheap to replace.
Most opticians will adjust a frame and replace pads for free or close to it, whether or not you bought from them.
Coated lenses, blue light coatings included, scratch the same way; whether that coating earns its price is covered in the do blue light glasses work guide.
Sunglass lenses carry more coatings than clear lenses, so the how to clean sunglasses guide adds the rules for polarized, mirrored and gradient lenses.
Frequently asked questions
What is the best thing to clean eyeglasses with?
Lukewarm water, one drop of plain washing-up liquid applied with your fingers, a thorough rinse, then blot dry with a clean microfibre cloth. Water does the work of removing grit; the cloth is only for drying. Avoid ammonia glass cleaner, alcohol, vinegar and anything paper based.
Why do my glasses get scratched even though I use a microfibre cloth?
Almost always because the lens was dry when you wiped it, or the cloth was dirty. Dust is mineral grit, and wiping a dry lens drags it across the coating. A microfibre cloth that has not been washed in months is holding all the grit it collected. Rinse first, and wash the cloth every week or two.
Can I use Windex or glass cleaner on my glasses?
No. Ammonia based cleaners degrade anti-reflective and other lens coatings, which is what produces the permanent hazy or crazed look that cleaning cannot fix. Use water and a drop of washing-up liquid instead.
How do I get scratches out of my glasses?
You cannot. Scratches on a coated lens cannot be repaired, and polishing kits and toothpaste remove the coating along with the scratch, which leaves the lens worse. A scratched lens can only be replaced. The useful step is preventing the next one.
Is it safe to clean glasses with hot water?
No. Heat makes the lens material and its coatings expand at different rates, and the coating cracks first, which is what crazing is. Use lukewarm water, and keep glasses out of dishwashers and hot cars for the same reason.
