Cleaning a Microscope

Regular cleaning of microscope is essential to ensure that it is optimally functioning. Cleaning is important to remove dirt, lens immersion oil and ensure disinfection. It involves cleaning the lenses, the body, the stage of the microscope and the light source. The microscope needs to be cleaned daily and the lenses need to be cleaned after each use.

Materials used for cleaning:

1. Lint free cloth
2. Lens paper
3. Lens cleaning solution
4. 70% ethanol
5. Detergent solution

Procedure for Cleaning Different Parts of the Microscope

1. The eyepiece shades, stage, focusing knob and nose piece are commonly touched during microscope operation, so these parts and the body of the microscope must be cleaned first to remove any stains with a neutral detergent /solution recommended by the manufacturer.
2. To clean the microscope eyepiece, objective lens, surfaces of the condenser and the light exit glass, moisten a lens paper with 1 to 2 drops of lens cleaning solution and clean the lens/ glass with a circular/spiral motion (as shown in the figure below).
   • Dry with a clean, dry piece of lens paper.
   • Use the Spiral Wiping Technique: Wipe from the center to the periphery in a circular motion.
   • The oil immersion lens should be cleaned after each use to ensure that immersion oil is not left on the surface.
3. The microscope surface and parts (except the lenses) need to be disinfected using 70% ethanol.

Figure: Cleaning of Lenses using the Spiral Wiping Technique. Source: How to Clean the Microscope

Important Considerations for Cleaning Microscopes

• Do not blow air to remove the dirt.
• Do not wipe the lens with an ordinary cloth. All the lenses should be cleaned with dry lens paper/lint-free cloth. 
• Never use spirit or alcohol or xylene to clean the lenses as these can damage them.
• Avoid using organic solvents that may damage plastic parts.
• Whenever possible, use the cleaning fluid recommended by the manufacturer.

Resources

• Laboratory Diagnosis of Tuberculosis by Sputum Smear Microscopy, GLI, 2013.
• Module for Laboratory Technicians, CTD, 2005.
• How to Clean and Sterilise Your Microscope, Olympus, Life Science Solutions, 2020.

Assessment