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How to Clean and Sterilize a Lab Microscope

Cleaning and disinfecting a microscope regularly is important to help keep lab technicians and research staff safe and healthy

by Olympus Corporation
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Viruses can remain infectious on surfaces like metal, glass, or plastic for hours to days. Consequently, cleaning and disinfecting a microscope regularly is important to help keep lab technicians and research staff safe and healthy.

Please read on for best practices to keep the microscope and optical system clean and sterilized.

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Cleaning and disinfecting a lab microscope frame

After a microscope is used, wipe down the frame if there is any noticeable dirt and impurities on the surfaces. Next, disinfect the surface to kill any germs. Disinfecting after cleaning helps to lower the risk of spreading infection to other lab members. In particular, the eyepiece shades, stage handle, focusing knob, and nosepiece are commonly touched during microscope operation, so these parts must be cleaned and sterilized carefully.

  • Cleaning the frame: To remove any stains, first wipe the frame with a piece of cloth soaked in a small amount of neutral detergent. Next, wipe the frame clean with a piece of cloth that has been immersed in lukewarm water. As it is cleaned, make sure not to touch the lens.
  • Disinfecting the frame: Using 70% ethanol is most recommended since it effectively disinfects the microscope without damaging the frame. Remember avoid using organic solvents except ethanol that may damage plastic parts.

As the microscope is cleaned and disinfected, always follow proper hand hygiene. Here are some important reminders:

  • Wear gloves when cleaning and disinfecting the microscope frame and optics.
  • Discard gloves after each cleaning, then wash hands with soap and water for 20 seconds. If soap and water aren’t available and hands don’t look noticeably dirty, then use an alcohol-based hand sanitizer that contains at least 60 percent alcohol.

Now that we’ve covered microscope frame cleaning best practices, let’s review how to properly clean the optical system.

Maintaining the cleanliness of the optical system

Just like with the microscope frame, always clean and disinfect optics immediately after use. Not only does this make the equipment safe and clean for other lab members, but it removes dust and contaminants that can affect observation, damage the lens surface, and impact image quality.

Detailed below are steps to help clean dust, dirt, and germs off the exposed areas of objectives, eyepieces, filters, and condensers. If internal or major cleaning is needed, please contact the local microscope manufacturers rep for assistance.

Spiral wiping technique: Wipe from the center to the periphery in a circular motion.

Steps to clean and disinfect microscope optical components

  1. First, inspect any dust on the lens surface using a loupe. If a loupe isn’t readily available, simply use an eyepiece and hold it up to the lens surface to magnify any dust or dirt.
  2. After inspection, remove any dirt and dust stuck to the surface with a blower.
  3. Next, grab a piece of lens paper and fold it around a finger to create a point. It’s important to use lens paper for this step rather than facial tissues, lab tissues, or paper towels. Consumer tissues contain loose, coarse fibers that can scratch the lens surface or break off and remain on the lens. For optics with a smaller surface area, create a fine point by folding the tissue into a triangle.
  4. Put a small amount of lens cleaning fluid or cleaning mixture on the tip of the lens paper. 70% ethanol is recommended because it can effectively and safely clean and disinfect the surface.
  5. When cleaning the lens surface, wipe from the center to the periphery in a circular motion, as shown to the right:
    • Larger surfaces, such as a glass plate, may be too large to wipe using this technique. In this case, simply hold the lens paper on the surface while rotating the object slowly and touching only the edges.
    • To clean the surfaces of the condenser and the light exit glass, hold a piece of lens paper between the middle and index fingers, then fold and wrap it around the index finger. Hold the tissue down with the thumb while wiping the lens surfaces clean.
    • As the optical components are cleaned, always discard each lens paper after a single use.
  6. Look for any remaining dust or residue using an eyepiece or loupe to confirm that the lens is clean. If color reflected from the lens surface looks uneven, this indicates that dust specks and dirt remain on the lens. In this case, begin the cleaning process again until the lens is free of contaminants.
  7. Once the optical accessory is clean, immediately reattach the cleaned component on the microscope to keep the system organized.

These seven steps offer basic instructions to clean optics. 

Keeping a clean microscope workspace

In addition to cleaning and disinfecting the microscope and optics regularly, also consider the environment around it. Use the microscope in a clean place without vibration or tilt. The room must also be moisture-free to avoid mold and have a consistent temperature. When the microscope is stored, make sure to cover it to prevent exposure to dust.

*Please note that product deterioration caused by excessive use is generally not covered by the manufacturer warranty.