Your binoculars may have lens caps. Maybe it even has caps for both the eyepieces and the objective lenses. But unless you never take them off to use your binoculars, your lenses are going to get dirty.
Tiny (or not so tiny) bits of dirt and dust are going to accumulate on the surfaces. Someone (not you, right?) might spill something, like food, on them. When this happens, not as much light is going to go into or come out of the lenses as it should.
You shouldn’t clean your binoculars (or other optics, like telescopes, spotting scopes, rifle scopes) every time you use them. In fact, cleaning them as little as possible is a good idea. The less you clean them, the smaller is the chance that you’ll damage the lens coatings.
If you manage to remove or degrade the coatings (an unfortunate occurrence), you can’t get them back to factory condition again. Once part of those ultra-thin coatings is gone, it’s gone forever.
Wrong Way – Do Not Enter
Briefly, here’s what not to do to get your bino lenses clean.
- Don’t breathe on the lenses.Don’t use fluid intended for eyeglasses or windows.
- Don’t use fluid intended for eyeglasses or windows.
- Don’t use paper towels or facial tissue.
- Don’t rub them with your shirt.
- Don’t use a dirty cloth, even if it’s a microfiber cloth.
- Don’t rub harshly.
Maybe Yes, Maybe No
There are a couple of things that could be okay under the right circumstances.
Using canned air for loose grit is questionable. It should remove the loose dust particles just fine, but it may contain chemicals that could harm the lens coatings.
One type of brush you might use is sometimes called a lens blower brush. You squeeze the handle to release a puff of air towards the lens surface and then brush it away. A lens blower (without the brush) is also possible. The downside of these is that they might not blow away as much dirt as they bring in. Experimenting with different models may be your best option here.
Some binoculars have eyepiece cups that you can remove, mostly likely by unscrewing them. If your pair has these, remove them for better lens access.
The Right Stuff
Here then is my recommendation for the proper way to make your lenses gleam like new.
First, check your owner’s manual. It may have information about cleaning the lenses. If not, don’t despair. Just continue reading for some reliable tactics.
Remove any loose dust and dirt with a soft brush. You need to get the loose grit off the glass before doing any rubbing. Otherwise, the tiny pieces could act something like sandpaper, not only scraping away at the coatings but even wearing away bits of the glass itself.
Examine the lens at this point to see if it even needs any more cleaning. If not, your job is done. Move on to the next lens as needed.
If there is obvious grunge still on the lens, get a lens tissue, microfiber lens cloth, or even a Q-tip. Add lens cleaning solution or plain water and wipe the lens gently until clean.
You can get a lens cleaning kit that should have all needed materials. Altura, Carson, Swarovski, Nikon, Zeiss, and others all make fine kits. Apply the instructions above or those contained in the kit to complete your task.