Cleaning microscope objectives

Microscope objectives are often used in very close vicinity of samples. It is therefore not uncommon to find traces of material on an objective.

Cleaning an objective often involves special cleaning liquids, swabs, alcohol and/or pressurised air. However, this process is quite cumbersome since careful handling is required to avoid scratches on the lenses.


Ultrasonic cleaning is in principle a superior technique, since the cleaning can be performed ‘hands-free’. An easy way to place the objective in an ultrasonic bath is by using our BuBble bags. Put the objective in the bag, add demi water (not tap water since that may leave residues!) and place the bag 1-2 minutes in an ultrasonic bath. Afterwards, dry the lens with e.g. nitrogen or pressurised air to make it ready for the next use!


A few points of attention:

  • Keep the cleaning time short: after a few hours the lens, glue and coating may start to become damaged. 1-2 minutes in an ultrasonic bath is typically sufficient.
  • Some contamination may dissolve better in solvents than in water, however be careful with these solvents since they may degrade the objective. Only water (plus some soap) and the proper use of an ultrasonic bath should be sufficient in many situations.
  • Some objectives are not water tight, for example objectives with moving parts (‘spring-loaded’). These are better cleaned manually.