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Cleaning Binoculars and Spotting Scopes

It will happen. You've used your brand new binoculars a couple of times. They may even still have some of that new smell to them. Then you look down and see something on the lens surface of the eyepiece. Arrrghhhh! Dirt!

I know your pain. You hesitate. You feel violated. You want your new glass the way it was before—clean and unspoiled (or "unsoiled"). But you also knew this was coming. It had to. Birds don't live in an antiseptic environment and neither do you. Deep down you knew you couldn't protect your precious optics from the evils of a dirty world.

At this point your relationship enters a new phase. Whether you achieve long-lasting happiness will depend on how you plan to care for the precious glass in the days to come. Sad to say, many instruments die a premature death because their owners failed to use a little common sense.

The first issue is when and how often to clean your optics. Your motto here should be "moderation in all things." Obviously, a major ketchup or mayo spill from your sandwich or a dunking in the mud will require your immediate attention. But what about the dust, dirt, and smudges that accumulate with everyday use? When does this stuff become an issue?

Probably not as often as you think. For example, I've worn eyeglasses all my life, and mostly outdoors at that. Yet it truly amazes me just how dirty my specs can get before they affect my vision. That's when I clean, and not before. I treat my binoculars and scopes the same way. Painful experience has taught me that grabbing a lens cloth or lens pen every time I take my binoculars or scope out of its case is a bad habit. In fact, it can be downright disastrous.

It's a matter of odds. Every time you touch a lens surface, there is potential for real and permanent damage. Every time you decide to poke around delicate working parts to clean you are taking a big chance. There is no worse feeling in the world than to realize you just damaged an expensive optic because you got a little sloppy or too ambitious with the cleaning. I know, I've been there. If this scares you a little, it should. Cleaning optics is something to be taken seriously. Yet I've seen people absentmindedly swab their optics down almost hourly.

The problem is that any hard piece of grit, sand, or metal that has landed on a lens surface or near a focusing mechanism must be removed carefully before you hit your binoculars with a cleaning cloth or pen. It's these little things that you often don't see that do the damage. One piece of sand trapped between your lens cloth and lens as you swab, even with slight pressure, can produce a scratch, if not in the glass, at least in the coating.

And because of static charges, these little pests tend to adhere stubbornly to lens surfaces. It's not always as easy as blowing them off with a puff of breath or removing them quickly with a few swipes of a cloth or brush. And because oil or grease can act as a grit magnet, you should think twice about ever applying lubricants to external working parts of optics. In the end, as you attempt to wipe off the inevitable buildup of grit and grime, you run the risk of driving the stuff deeper into focusing mechanisms and other moving parts.

But eventually, despite the risks, you will need to clean. This is neither a technical nor complex procedure, nor does it require many special tools, but it will require your full attention. It can, of course, be done in the field, but I prefer to do it at home where I can control the light and I won't be tempted to rush the job and make a costly mistake.

First, the lenses. Before you apply pressure with a cloth or lens tissue, you must be sure that all sand and grit have been removed. This is best done by gently swabbing with a soft lens brush. (Be sure you are using a clean brush—check before you start!) This is essentially a simple operation, but it must be done right to be effective. The trick is to get unwanted particles off the lens instead of just moving them around. Most people just start from the center of the lens surface and work toward the edges. But this usually just pushes grit particles up against the lens housing where they are even harder to see, let alone remove. You can work from the edge inward, but then you run the risk of pushing abrasive particles across the lens surface.

The way I beat this problem is to hold the lens upside down as I brush. Then, no matter which way I brush, particles are more likely to fall off. This requires that you hold the lens up high enough over your head to see—not as comfortable as a more conventional approach, but definitely more effective.

When you are absolutely sure the grit has been removed, it is time to clean with a good lens cloth, lens pen, or lens tissue. Each has advantages. I have had good results with all three.

The lens cloths I refer to are not the cheap little things that come with your binoculars—those are almost useless. I mean the high-tech cloths, usually sold separately, that are made of special fibers that clean but do not scratch, fragile lens coatings. The best are the microfiber type. The beauty of all these is that they can be washed and used over and over again. I've had some that are still cleaning after 10 years of use. But the disadvantage of lens cloths is that they are not very effective at cleaning hard to reach areas, such as lens edges. It sometimes helps to make a little fold in the cloth and rub it against the edge of the lens where it meets the housing, but under no circumstance should you wrap the cloth around a hard pointed object to clean these areas.

Lens pens are much better at cleaning around the edges of lenses. That, and the fact that they come with a built-in brush and supply of cleaning chemical, make them very practical. On the downside, they are easier to misplace (at least for me) than cloths, and can be rendered useless if the cap on the lens cleaner works loose and allows the cleaner to pick up dirt and grit from the environment. And, of course, once the chemical in the lens cap is exhausted, it's time for another pen.

Lens tissues are a less-used option these days. They are not reusable and vary somewhat from brand to brand in effectiveness. Other than that, they are very much like lens cloths in their use, but offer the additional advantage of always having something clean at hand.

I am not a big fan of chemicals. In an extreme case, when I need to wash a lens surface I just use water, because all my equipment is waterproof anyway. If you do go with a chemical, do not use household glass cleaners. They are not designed for delicate lens coatings and can even cause separation of lens elements with repeated use. And speaking of chemicals, be careful when using insect repellents that contain DEET around optical equipment. I have used this stuff as a paint remover in a pinch. Enough said.

The next part of your binoculars or scope that may need attention is the focusing mechanism area. This is especially true of external focus instruments that have moving parts exposed to the elements. Internal focus instruments are much less likely to need attention here, but they still have a focusing wheel that can become clogged with dirt.

The important thing when working in this area is not to do anything rash. Never, under any circumstances, should you attempt to disassemble any part of your optics in order to clean them. If your focus mechanism is acting up and you've already done everything you can do to clean it within the manufacturer's recommendations, then it's time to send it in for repair and a professional cleaning. In my experience, a problem that develops in the focusing mechanism is nearly always a result of worn-out or defective parts and only rarely the result of dirt. After all, binoculars and scopes are designed to be used in a dirty world in the first place. And once you take an instrument apart, you can forget your warranty, and rightfully so. No one wants to work on a boxful of parts after you played amateur repairperson.

But let's say you got a little clumsy and dropped your binoculars or scope into a foot of oozy marsh mud. What to do?

The absolute safest option, especially if your model is not waterproof, is to send it to a professional to have it cleaned. However, this won't be cheap. In fact, it may actually cost more than your instrument is worth. This is something you should check before you box it up and ship it.

Of course, you can try to clean the instrument yourself. Keep in mind that this is damage control—cleaning without adding to the damage. You may not be able to save your instrument, but at least you will have done everything you could.

First, work within your manufacturer's recommendations. If your instrument is not waterproof, it was never intended to be submerged. Dunking it in a sink full of water to clean it, then, is asking for a leak—a much more serious problem than a little mud. Even if your model is waterproof, this should be used as a last resort. And sticking your instrument under a running faucet or spraying with a hose is even worse because of the high pressure of the water. The safest, albeit slowest, way to go is with a wet rag and a spray bottle of water.

Begin by gently spraying the lenses with water. Concentrate the spray at the center of the lens, rather than the edge, to keep water out of the seals, especially if your model is not waterproof. When most of the mud is off, proceed to clean the rest of the instrument. Do not attempt to clean the lenses further until all the mud has been removed from the instrument. There's still too much mud around to touch the lenses yet. And be prepared for the worst as your lenses come clean—they may have hit something hard in the mud and suffered damage. If not, you can breathe a sigh of relief.

When the lenses are free of mud, take a wet rag and clean off the body of the binoculars, including the focusing mechanism. You can also use the spray bottle if you are cleaning a waterproof instrument, but the wet rag alone is safer if you are cleaning a nonwaterproof instrument. Do your best to work the mud away from any recesses around moving parts. You don't want any more dirt working into moving parts. Once all the mud is off, check the focusing system to be sure it works correctly. If so, you can then proceed to finish cleaning the lenses. If not, well, you can't save them all. But at least you tried.