Cleaning optics


Well-Known Member
Mar 18, 2003
Is it safe to use glass cleaner on a qtip or cotton swab to clean the optics on a scope?
Can a person use alcohol? If there is optical coatings on the external lenses will glass cleaner or alcohol hurt them?
What method of cleaning works best for you to get the optics spot and streak free?
I have a couple spots of something on the obj of my NF I'd like to get off, not sure what the hell it is though. Every "simple" thing I've tried doesn't touch it but, here's the catch... you can't even see the spots until you fog it up from breathing on it, it's basically invisible otherwise. It doesn't smear like oil or anything and it didn't rub off either????????

Is MEK or ALCOHOL in order here??? I hate the thought of using MEK on anything, the stuff's NAAAAAASTY!!! One good wiff of that crap would take years off ones life I think!!!

Someone here said MEK is what NF "recommended."
As you know, proper cleaning and maintenance are important parts of obtaining the optimum level of performance from your riflescope.

Lenses: scope lenses are coated to reduce light reflection and light absorption. They should be cleaned as carefully as you would clean a camera lens. Use a lens brush to remove dust. If the lens is dirty, clean with pure alcohol, a grade of pharmaceutical acetone (keep it off of wood stocks), or pure water on a cotton swab.

Clean the lenses as you would a fine camera lens. Use a lens brush to remove dust (or simply blow off the particles). Fingerprints and smudges that cannot be removed by brushing can be removed with a good grade of glass cleaner. For example, Leupold uses a pharmaceutical grade of acetone for 99% of their lens cleaning. Use a cotton swab for application of the cleaner directly to the lens. Shake off the excess acetone so that it does not drip. Start in the center of the lens and work the tip to the outer edge of the glass. Use as frequently as necessary to keep the lenses bright and clean.

[ 06-01-2003: Message edited by: thequickad ]

[ 06-01-2003: Message edited by: thequickad ]
When tempted to keep your lenses constantly, perfectly, dust free - just say no!

Every time you clean your lenses, you subject them to a mistake on your part that can have long lasting ramifications. A little dust on the objective, or ocular for that matter, doesn't degrade the image in any way that our poor little eyes can actually see anyhow.

Now, a dirty little secret I found out about the hard way is the effect of suspended particles of tree sap/pollen that are released during spring and early summer. If you find a fine coating of hazy material (or if your lens turns a light shade of green!), clean it immediately! That stuff just will not come off completely after it dries...

Now when I do clean my telescopes, riflescopes and camera lenses, I use the same process.

Find the purest Isopropyl alcohol you can (right now, I've got 99+% pure). The rationale for this among my astronomer friends is that the detergents in the less pure stuff streak the lens and leave material behind.

Blow loose material off with low-pressure compressed air from the implement of your choice. Then, cotton swabs, with almost no pressure, should be used in a circular motion starting at the center of the lens and working outward. Be conscious of large particles that may scratch your glass. Change swabs often.

When the gunk is cleaned off, and only streaks are left, use a few Kleenex plain white unscented tissues (anal-retentive astronomers have found these to have the least amount of non-paper scented-lotion goo to further mess your lens up), with almost no pressure, first with a few drops of alcohol, then with less, to gently clean off the streaks.

That's it!

[ 06-01-2003: Message edited by: STL_Shooter ]
I'm the type that almost never clean mine but, I do take "every" precausion to keep crap off of them. My rational is the more you clean them, the more chance to scratch them or otherwise wear off the coatings.... and why, you can almost never see the crap on the lense anyway.

Well after several months of use, I noticed some haze and build up getting to the point I figured I'd clean it off and start over... I don't think I'd ever even cleaned it up to that point.

I'll try the alcohol and see what happens with the spots I got on mine. Thanks
Here's an email Jay sent me;

Hi Brent, I'm having a hard time logging on, I'm at my Aunt's house in Onalaska, WI. Tell the fellow with the question about cleaning scope lens NOT to use Windex type cleaners, they'll take the coatings off, alcohol is fine but pure Acetone works great, per Burris CS. Take Care, Jay Gorski
I agree with the others in the avoidance of general cleaning which is tough for me being a clean freak however when I must I have found that a very soft new paint brush and compressed air works great. MEK for serious cleaning is what I was told by NF as it disolves about anything and evaporates instantly. I was very surprised at this answer fearing damage to the ever worshipped coatings. NF reiterated that it is what thew use in their lab.
Camel hair brush to get the grit off, fogging lens with your breath and cleaning with a Q-tip cirular motion from center of lens out. For removal of stubborn stains, use a comercial lens solution. Zeiss makes a good one. I've used this method for 30 years when cleaning pro grade photographic lens and have never damaged the surface of the lens nor the coating.

Since I almost always carry a camera with me when I am shooting and hunting I always have a Lenspen in the cameracase. For most lens cleaning, camera, binocs, scopes - I brush the lens with the little brush end of the Lenspen, then simply moisten the lens by breathing on it and then use the Lenspen chamois pad, going around in diminishing circles while spinning the pen a bit. By the way, Lenspens are usually much cheaper in camera stores than sporting goods stores.
Another excellent lens cleaning tool is the specially made (micro-fiber) lens cleaning cloth with the loop design that will even remove oil from lenses, available at camera stores.
I would much rather brush a lens clean than have to wipe it, but when your scope is so mucked-up that the image is in black and white, you pretty much have to clean it.
I worry more about scratching the surface when cleaning so never rub anything hard (Lenspen, cleanex, my shirt-tail or whatever) and agree that lenses work just fine with a certain degree of specs and spots.
Last resort is lens cleaning fluid on a piece of lens cleaning paper from Zeiss, Swaro or wherever I can get some but usually the little micro-fiber cloth or Lenspen does the job. Have used clear, clean mountain lake and river water that did as good a job as the cleaning fluid - no spots.
I have had a couple of nasty experiences with lens, such as dragging the front lens of my 56mm binocs onto a steel barb as I crossed a barbed wire fence and - no marks or scratches. Worst was with a Nikon 80-200 f2.8 ED lens that a horse put into a tree - cleaning that lens involved getting all the shattered glass from the filter out of the objective.
I find if I put lens shades on the bigger scopes the objective stays pretty clean and clear of dust.
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