It’s easier than you might think to keep your optics in top condition: a little goes a long way, says Leica technician David Slater.

David Slater is one of Leica’s technicians and is, among other things, an expert on cleaning and repairing sport optics. He cleans and services high numbers of binoculars and spotting scopes every year.

“Modern optics are so well made that you can actually do most things you need to maintain them yourself,” he enthuses. According to David, the most common mistakes people make are pressing too hard, using the wrong kind of cloth or simply not cleaning at all.

Thirty years of dirt 

“Some of the binoculars I see are 20 or 30 years old and have never been cleaned. Optically, they’re still brilliant, but the grime has had a long time to build up and this can make the eye cups stiff and difficult to adjust.”

Does it take a lot to remove 30 years of dirt? “Not really, considering,” says David. “A good wash in warm, soapy water should get most, if not all of it moving and a cleaning wipe should get rid of any particularly stubborn or ingrained particles.

“Don’t rub too hard though,” he adds. “If you do, you risk scratching the lens itself or damaging the coating by grinding small particles of grit against the glass. The soapy water should loosen everything. We never have to worry about water getting inside as all our binoculars are fully waterproof and nitrogen sealed so the water do the hard work for us.”

With premium binoculars and many others, there’s no need to use any lubricant. If you do, you’ll just end up moving the dirt around rather than getting rid of it. “The moving parts on our binoculars are designed to function without any need for lubricant, so that performance will be perfect all the way across the temperature range, from extreme heat to extreme cold.”

On most modern models of binocular, you can also remove the eye cups to give them a really thorough clean. With Leica’s latest models, they can simply be pulled off when extended and slot back on easily. If you’re struggling to shift dirt from a hard to reach crack, David advises using a household wipe wrapped around a wooden coffee stirrer stick (the kind you can pick up for free next to the napkins in most big chains) – just make sure it hasn’t been used to stir coffee first!

Finally, once you’ve washed the dirt off, David stresses the importance of wiping away any water droplets and drying the product properly – ideally in a warm place. His preferred way to remove any smears or marks on lenses left over from washing is by breathing on them then wiping gently with a clean, good quality microfiber lens cloth.

How long is a piece of string?

Cleaning optics is as simple as that: the hard part is remembering to do it often enough. And how often is often enough? “How long is a piece of string?” laughs David, “It really depends on what sort of use you’re giving the product and how often you’re using it.

“Obviously, if you drop your binoculars in a bog or they get thoroughly filthy during an outing, you should clean them as soon as you get home. If you’re using your scope or binoculars near salt water, for instance for sea bird watching, they’ll need cleaning more often to prevent invisible salt residues building up and potentially damaging coatings. Sometimes the product itself will tell you it needs a clean: if eye cups start to stick that often means that dirt or dust has built up inside and the problem can usually be solved with a quick clean.”

Another simple but surprising tip that David has is to use rain guards to protect the eye-pieces – not only from the weather but from your lunch with your binos around your neck. “I’ve had to clean so many sandwich crumbs out of eye-cups that I’m considering suggesting that HQ renames the rain guards as ‘lunch guards’,” David laughs. “And it’s no excuse if you’ve lost them, or the caps for the objective lenses. We’ll supply replacements for Leica binoculars free of charge. All you have to do is call customer care and let them know the model and age.”


Don’t try this at home?

Is there anything you shouldn’t try at home? “If you’ve dropped or banged your binoculars or telescope check carefully for any dents,” advises David. Modern rubber armouring and tubes are tough but sometimes a hard knock on an unfortunately placed stone can damage the outer casing and this could compromise the waterproofing. If you’re in any doubt, David recommends taking the product to your local dealer or calling the manufacturer’s customer care department. Most repairs can be done under warranty (Leica’s current warranty on optics is 10 years) and many more are carried out free of charge on a goodwill basis.

Essential home maintenance kit:

  • household cleaning wipes – excellent for removing dirt, dust and watermarks when out and about
  • washing up liquid – for making warm, soapy water to soak off mud and mess
  • a clean, good quality microfiber lens cloth for a final dry and gentle polish
  • an air duster, the best way to blow away dry grit and sandwich crumbs without smearing or scratching