We should keep your sunglasses clean, but we would not want to damage your sunglasses while cleaning them  Here are something you should know about how to clean your sunglasses.

About the lens coatings

Most of the lenses of sunglasses are with coatings, like mirror coating, scratch-resistant coating, anti-fog coating and UV-blocking coating.  The scratches you seen may not be on the surface of lenses but on the lens coatings, therefore, we should avoid any possible damage on the lens coatings while cleaning the sunglasses.  Most lens coatings are using a method called Chemical Vapor Deposition to apply various thin films of minerals onto the lens. What the film is really depends on the chemical formula used by the lens manufacturers.  Aluminum, silver or even gold may be used for the mirror coating of lens, and aluminum is the most commonly used one, as it is cheapest.  Any substances which reacts with the aluminum may cause a permanent damage on the mirror coating of the sunglasses.  In order to keep the lens of your sunglasses scratch-free as long as possible, you should carefully protect such thin layer of lens coatings.

 Most common way to clean the lenses of sunglasses

Many people clean the lenses of their sunglasses, by breathing warm, damp air on your lenses and gently wiping the fog off with a paper towel, shirt, jumper or handkerchief.  Later, the plastic lenses got scratches on its surface after times of such cleaning processes.  Shirts, jumpers or handkerchiefs may have sand, dirt or similar abrasive particles which will scratch the lens of your sunglasses or wear off its coatings.  Wood tissue of the paper towel may be hard enough to cause scratches.  You may then order a new pair of sunglasses in less than a year.  Some of you may be looking for the way to clean your sunglasses with scratching it.

 Our suggested approach to clean your sunglasses

The best way we are recommended it to wash your sunglasses with cold or lukewarm water and mild hand soaps (not Palmolive or Dawn) or baby soaps and dry your sunglasses thoroughly with a clean microfiber cloth.  This method is not new and many people clean their sunglasses in the same way.  However, here are something you should avoid.

• Never dry your lenses with paper towel or even cotton towels, as wood tissue of the paper towel dust or small abrasive particles inside cotton towel can scratch the lens of your sunglasses or its coatings.
• Use microfiber to dry your lens. Microfiber clothes are made up with microfiber, which is very thin fiber.  Microfiber is 1/20 the diameter of a strand of silk, which is 1/5 of a human hair.  A square inch of microfiber has about 200,000 fibers.  It mean that dusts or abrasive particles are not easy to fill in the fibers of microfiber clothes.  That is why a microfiber cloth is normally provided in your sunglasses set.  Just a side note, if you need to wash your microfiber cloth, just wash it with cold water, to let air dry. Do not use laundry soap that contains fabric softener.  Because heat and fabric softeners are the enemy of microfiber!
• Don’t wash your sunglasses with hot water, even it is in winter, as it will reduce the lifespan on some lens with coating
• Don’t use window cleaner or toothpaste to clean the lens of your sunglasses. Although it is common method to clean your window glasses with window cleaner, like Windex, the lens of your sunglasses is not actually glasses, the window cleaner is a very strong chemical cleaning agent, which may contains ammonia.  Ammonia will damage your lenses and your frame.  We note that a few Youtube videos talking about white toothpaste as an anti-fog agent for the lens of sunglasses, but we never recommend it.  Toothpaste contains of small and tiny abrasive particles to remove food residues from your teeth, which may cause physical damages on the lens, when you are rubbing the lens with toothpaste.  In addition, most toothpastes are fluoride-based.  Fluoride compounds are considered as active ingredients, which may react with the lens coating of your sunglasses and cause an irreversible damage.
• Similarly, don’t use household detergents or soaps, as today’s cleaning agents are concentrated and powerful enough to slowly disintegrate the lens coatings. We recommend to use the mild hand soaps or baby soaps and only one or two small drops are enough for the cleaning purposes of your sunglasses.
• Lens cleaner spray can take place of water and mild hand soaps. But, why do you need to spend extra penny on the spray?
• Wash your hands thoroughly to remove grease from your hands and fingers. Then, wish away dust from your lens of sunglasses with cold or lukewarm running tap water.  Then apply one or two tiny drops of mild hand soaps to your fingers and rub the both sides of the lens gently and then the frame edge, nose pieces and the temples.  Rinse the sunglasses with tap water completely.  If the tap water is hard, it contains dissolved minerals of calcium and magnesium, you will need to do a final rinse with distilled water.  Otherwise, you may find the lens hazy later because the traces of salt is on the lens after water dry.  Shake your sunglasses gently to remove the excessive water drops on the sunglasses and then dry it with a clean microfiber cloths thoroughly.

Once you learn how to clean your sunglasses, but how often you should clean your sunglasses --- the time between cleanings depends on whether you have a need to clean it.  Surely, you should clean it when they are so dirty or greasy that you cannot see clearly.  After you clean in properly, place it in a protective case and keep it away from extreme temperature and dusts.

 However, you must clean it after each time of outdoor activities, especially, water sports.  Sea water contains salt.  If you don’t wash your sunglasses after water sports in the beach, either traces of salt or sand particles may be on the surfaces of lens on the both sides.  And you may scratch your lens when you try to remove by rubbing the lens even with a clean microfiber cloth.  Why?  Imagine if there are sand on your lens, and rubbing the lens with microfiber cloth just cause the sand slide on the lens and cause scratches.  In addition, sea water can cause rusting on the metal parts of your sunglasses, like the metal spring hinges.  What if after games in swimming pool?  Water in the swimming pools is sanitated with chemical compounds, in order to ensure the hygiene in swimming pools.  The chloride-based compounds are commonly used, which may react with the lens coatings.  Therefore, wash your sunglasses with lukewarm tap water to remove the sand or sea water right after having water sports or even just enjoy your sunshine in the swimming pool or on the beach.

The above tips may apply for cleaning your eyeglasses as well.

Washing your sunglasses with ultrasonic cleaner

If your sunglasses has not been cleaned for a period of time and greases and dirt built up on the nose pieces and other components of the frame, it may become impossible to keep clean.  Then you may need to ask assistance from your local eye care professional.  Sometimes, sunglasses can be cleaned more thoroughly with an ultrasonic cleaning machine and the yellowish silicon nose pieces can be replaced with new crystal clear ones.

However, if you have an ultrasonic cleaner at home and want to wash or clean your sunglasses with it, please do it carefully.  Don’t use any strong cleaning agent, except for one to two drops of mild hand soaps.  Don’t you hot water, even the user manuals of ultrasonic cleaner suggest it.  Don’t sunk your sunglasses in the ultrasonic cleaner too long (less than three minutes).  A real ultrasonic cleaner is very powerful, it can make a tin foil or aluminum household foil with hundreds of hole within 30 minutes.  Remember most of mirror coatings of sunglasses are made of aluminum.  Google tin foil test for ultrasonic cleaner and you will see why.

by ZACWAY EYEWEAR

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