How to Clean Microscope Lenses

A smudged lens can drastically reduce visibility and can even trick you into thinking you’re looking at something that you’re not. However, cleaning a microscope lens is actually a very easy process. It’s especially hassle-free if you take care of it properly with each use instead of letting it get visibly grimy and dirty. Below, we go over a few simple steps to help you clean your microscope lenses. Remember to consult the lens manufacturer’s guidelines for specific advice.

Find the Dirt on Your Microscope Lens

First, determine whether the debris is on one of your objective lenses or the eyepiece lens. If you notice a spot when you are looking in the microscope and only see it at one power, the dirt is more than likely located on the objective lens.

However, if you see the dirt in the same spot using each objective lens, then it is probably on the outside of the eyepiece lens. If you can turn your eyepiece, turn it to see if the spot moves. If it does, the dirt is in on the eyepiece lens. 

Cleaning the Eyepiece Lens

Any dust that stays on your lens could scratch the optical glass and coating. Gently blow the dust off the surface of the lens with a squeeze bulb or a compressed air can like the kind used to clean keyboards. Avoid using a puff of air from your mouth since you don’t want to accidentally get saliva on the lens you are trying to clean. If the mark remains, your first attempt at using a solvent should be with distilled water on a Kimwipe, gently wiping the lens. If that doesn’t produce the intended results, you can move up to isopropyl alcohol or an optical lens cleaner intended for microscopes. 

Cleaning Objective Lenses

If you are using immersion oil in your microscopy, gently wipe the excess oil off the lens with lint-free lens paper. Then, apply a drop of optical lens cleaner to a large cotton swab (the stick from conventional swabs can scratch the lens) and use a spiral pattern to clean the objective, starting from the outside and moving to the center, then back again. Repeat this spiral motion a few more times and avoid using other wiping techniques as they will only spread the dirt around the lens.  

Microscope Cleaning Kits

Microscope cleaning kits are an economical way to stock up on supplies. AmScope carries a range of microscope and camera cleaning kits to help you protect your equipment and keep it clean.

Things to Avoid

There are many wrong ways to clean microscope lenses, like using the following:

Acetone: This solvent can dissolve plastic and paint and damage lenses.

Tap water: You’re likely to do more harm than good, as there are minerals that could leave spots or marks after the water evaporates.

Tissue paper or paper towels: Both are too abrasive for delicate lenses and can scratch them.

Keeping It Clean: Always Use a Microscope Cover

The first step to a clean microscope really is an easy one–keep your microscope covered. Most microscopes come with a cover. If yours has been damaged or lost, it’s easy and relatively inexpensive to find and order a new one. Microscope covers can’t keep you from accidentally leaving fingerprints on the glass, but it can prevent dust buildup. Sometimes just a little bit of dust can be invisible to the naked eye, but can significantly impede your view of the specimen. Microscope covers are especially important in busy labs, where high foot traffic can increase the odds of sticky or damaging substances getting spilled on equipment. 

Wear Gloves

Gloves aren’t just used to protect your fingers from hazardous substances. They can also go a long way in protecting sensitive objects from your fingers. Thinking about all the substances that collect on our fingers over the course of a day isn’t necessarily a pleasant thought, and is definitely a good argument for frequent hand washing. However, that extra latex layer of protection is a foolproof barrier between the oils, dirt, and fluids that could be built up on your fingertips and the sensitive microscope lens. 

Microscopes can be finicky if mistreated, so it’s wise to adhere to the manufacturer’s protocol when cleaning them. If you no longer have the data sheets that came with the microscope, a customer service representative should be able to answer all your cleaning questions. Keeping your microscope covered and treating it carefully should help keep the lenses clean and lasting a lifetime.