The best way to avoid having to clean the lenses on your microscope is to use it carefully and keep it covered when not in use. If a lens gets dirty or gummed up, here's what you should do. Most microscope specialists say the less cleaning of a microscope lens, the better. Eventually, the time will come when you will have to give them a good cleaning. Below are some tips on how to correctly do this. First, try to locate the dirt. Is it on the eyepiece lens or objective lens? If you see a spot when looking in the microscope and you see it at all powers it's probably on the outside of the eyepiece lens. If your eyepiece lens turns, turn it and see if the spot moves as well. If so, the dirt is on the eyepiece lens (if not, the dirt is internal and you should probably have it cleaned by a professional). If you only see it at one power, the dirt is most likely on that particular objective lens. Sometimes all you need to do is blow off the residue. Use a squeeze bulb or one of the camera lens cleaner bulbs with the camel hair brush on the end.

If you need more, you can use the compressed air cans that are sometimes used to clean computer keyboards. Do not use any sprays with cleaners. Once blown clean, lightly wipe the lens with Kimwipes or another approved lens cloth. Another good cleaning tissue is Kodak Lens Tissue (available at photo stores) In lieu of a brush, you can use the paper. Roll the tissue into a tube and tear it in half, with the feathery torn ends together. Use it as a one-time brush. Use several for very dirty lenses. A regular lens brush can hold grit and cause scratching. If the grime is still there, you will need to use a solvent. When using solvents, put a drop or two on the paper then hold it against the lens for a few seconds to dissolve the crud. Then lightly wipe it free. Distilled water is the first solvent recommened. If that does not work, try alcohol. Isopropyl alcohol is one of the best solvents but it must be at least 90%+ pure (do not use rubbing alcohol, 30% water). Everclear which is grain alcohol (you must be 21!) can also be used but it doesn't do as well in dissolving crud.

If you have something like Balsam stuck on the lens, you must resort to a stronger solvent like Acetone or Xylene. Acetone should never be put on plastic parts as it dissolves most paints and plastics. A lens cleaning solution such as that in the Microscope Cleaning Kit works well for cleaning lenses. Some people swear by a solution called ROR, although we have never tried it. When adding the solvent, put only a small amount on the kimwipe and always apply it from the underside going upward to the lens. This will keep the liquid from running down into the lens. Do not remove the lenses from the instrument unless absolutely necessary. If you are using a 100x objective with immersion oil, just simply wipe the excess oil off the lens with a kimwipe after use. Occasionally dust may build up on the lightly oiled surface so if you wish to completely remove the oil then you must use an oil soluble solvent. For the Cargille Type A or B immersion oil that we sell, you can use Naptha, Xylene, or turpentine (use very small amounts on the kimwipe).

Do not use water, alcohol or acetone as the oil is insoluble to these solvents. To remove other oily substances, we recommend using the detergent called Wisk and prepare a solution of 1 part Wisk to 100 parts water. Try not to remove the lenses from your microscope unless absolutely necessary and remember to keep it covered as dust is the number one enemy!The best way to keep lenses and filters clean is not to get them get dirty in the first place! This may sound trite, but everysharper image air purifier blinking blue light cleaning carries with it a very small risk of causing problems. air purifier worth itThe major problem is themr air duct cleaningScratching occurs when something harder than glass (or the optical

coating) is rubbed on the lens. Of course lens cleaning tissues, cloths, brushes and fluids aren't harder than glass, but dust and dirt may be. Hardness can be measured on the Knoop scale. For our purposes here it doesn't really matter what the numbers mean, but it is important to know that a material with a higher number will scratch a material with a lower number. Here are some typical values: BK7 glass (typical optical glass) MgF2  (typical lens coating) Soda Lime glass (e.g. microscope slides) 100-800 depending on type As you can see, coatings and optical glass have a hardness in the 450-600 range. is pretty hard, harder than most metals for example. Try scratching a microscope slide with a pen knife. You won't be able to do it (but don't try this with your lens, just inFluorite (a lens material used by Canon in their "L" series telephoto lenses) isn't very hard at all, and that's at least one reason why fluorite lens elements

are used between regular glass elements. If a fluorite element was used as the front element in a lens it would easily scratch, so if the design calls for that, a permanent multicoated flat glass "filter" element is used in front of it - and that's why some of the long Canon telephotos use such a fixed "filter". While many metals are softer than optical glass and won't scratch it, many minerals areSand (quartz) will easily scratch optical glasses and coatings, Many silicate minerals such as Feldspars - which make up most of the earth's crust (e.g. Granite) - are also hard enough to scratch optical glass. A lot of "dust" and "dirt" contain bits of ground up rock, and that's what can scratch your lens orThe particles can be too small to see and still do damage. The first step in cleaning an optical surface is to gently remove the dust. this with a blower (either a bulb blower or some form of compressed gas) or a soft brush. Hopefully this will remove all the particles of hard minerals from the surface without

While blowing or brushing can remove surface dust, it won't remove things like oil or material stuck to the lens, such as the residue of sea spray left on the lens after the water evaporates (i.e. salt). To remove these material a solvent is probably required, either water based (to remove water soluble compounds) or something which dissolves oil, such as an alcohol. Solvents should always be applied on some sort of tissue, never pouredYou don't want excess liquid getting inside the lens where it can, for example, dissolve lubricating oils and redeposit them on internal elements. You can buy a number of  commercial lens cleaning fluids or, if you can find them, you can use pure alcohols such as methanol, ethanol or iso-propanol. preferred solvent, but it can be toxic if misused and it may be difficult to find pure. (ordinary "alcohol") and Iso-propanol are much less toxic and easier to find. you use an alcohol make sure it's pure and doesn't have some sort of non-volatile

You can also try distilled water (water without any minerals dissolved in it). One way to put a film of "distilled" water on a surface is to breath on it. water vapor in your breath will condense on a cooler surface as pure water. wipe the condensation off the surface with a lens tissue or cloth. One solvent to avoid or to use with great care is Acetone. It's very, very good atHowever it's also very, very good at dissolving plastics and paint. also difficult to find commercially in a pure form. Unless you have a surface so badly contaminated that Methanol won't clean it, I'd avoid Acetone. However if you get something like tar on the glass (how you'd do that, I don't know), then Acetone might be the only thing that will remove it.  You might also want to avoid household glass cleaners (like Windex), which may contain things like ammonia and dyes. If you want to be safe, stick with the commercially available lens cleaning fluids (see below).

A word about lens tissues and lens cloths. Make sure they are clean. Lens tissues should be used once then thrown away. The very last thing you want to be wiping across your lens is a tissue with a piece of grit embedded in it! should be washed frequently and kept in a clean plastic bag when not in use. cloths are excellent and the only type of cloth I would use myself. They are made of a very, very small fibers made of a polyester/polyamide material. often as small as 1 micron in diameter - which is 1/100th of the diameter of a human hair.The fibers are also often wedge shaped or triangular rather than smooth andThey act to "suck up" dirt and oil when wiped over a surface and absorb them via a mechanism which resembles capillary action between the tiny fibers. It's sometimes said that it's more difficult to clean multicoated lenses and filters than uncoated versions, but that isn't true. What is true is that oil is much more visible on multicoated optics,

so it's more difficult to remove every visible trace. For example, a grease smear (possibly left over from a fingerprint) which shows up on a multicoated filter would be invisible on anThere would be the same amount of contamination on both. The oil is more visible on the multicoated filter because it negates the anti-reflection effect of the coating and so appears as a brighter spot. On an uncoated filter the surface reflectivity is essentially unaffected, so it's harder to see. It's also said that you need to take more care cleaning coated and multicoated optics thanThis isn't generally true for modern lenses. If a coating is properly applied, it can be as hard as the original glass and it bonds very strongly to the glass surface. Properly applied coatings can't be removed with lens cleaning solvents, nor can they beOf course anything is possible if the coating hasn't been appliedHowever for most modern "name brand" multicoated lenses and filters, normal

care is all that's needed for cleaning. However if you're cleaning older lenses then some extra care may be needed. I have no personal experience it's said that some coated lenses though the 1950s and maybe even as late as the 1960s had fairlyThe early Leitz 50/2 Summicron is sometimes cited as an example of a lens with a coating that can be easily scratched. It's also said that some early coatings don't adhere to the glass as well as modern coatings and can also be attacked by cleaning fluids containing ammonia (like Windex), so that's another factor to bear in mind when working with coated optics made before the 1960s. Just when should you clean a lens or filter? Well, the short answer is as infrequentlyIt actually takes quite a lot of dirt on an optical surface before the imageA surface with a lot of "cleaning marks" will do more damage than one with a few specs of dust. "Cleaning marks" tend to scatter light and so lower contrast in some situations.

So blow or brush loose dust off a lens when you see it there, but don't clean it "just to make sure". look dirty, leave it alone. There are lots of lens and filter cleaning accessories out there, too many to list them all. However here's a small selection that covers most needs and which certainly won't breakIf nothing else you should certainly keep a microfiber cloth or a lens pen in your camera bag. Portable Lens Care System This contains a micro-fiber lens cloth, several pre - moistened lens tissues, a bottle of lens cleaner spray (1/2 oz), some cotton tipped applicators, a retractable lens brush and a portable field case. Pretty much all you need to take care of your lenses and filters and a case to store it all in for $18.95 Lens Cleaner, 3 oz Spray If you already have brushes, microfiber cloths etc., you can just buy the lens cleaning fluid on micro-fiber lens cleaning cloth Great for removing grease marks from optical surfaces.