Caring for your Microscope
Microscopes can magnify dirt and smudges in the system so that a very small bit of dust or oil can become very visible. Moreover, many components have important optical coatings that are easily damaged by physical or chemical cleaning--even many solvents and wipes intended for cleaning optics can damage them. For that reason, it is best to keep the microscope clean in the first place by avoiding touching optical components and always using a dust cover.
If some dust is visible in the optical path, start with the least dangerous cleaning method and work your way up. The first line of defense is a puff of pure air. It is best not to use canned air because it has liquids in it that can condense on the optics and leave a residue. Instead use a rocked shaped puffer intended for cleaning optics. These can also be used on camera sensors and are safer than wipes. A soft brush intended for cleaning optics is the second tool. After that, gently wiping with soft wiping material infused with a solvent is a possibility.
Some people like to use their breath to lightly moisten optics, particularly eyepieces (which are often wipe-resistant), but this is a risky proposition as our breath is not pure water and small particle of saliva, mucus, or other substances can get on our optics in that way.
When using any liquid to clean, it is important to use a small amount and ensure it does not dissolve the adhesives nor infiltrate any place in the microscope besides the surface being cleaned.
Materials sometimes used to wipe optics include
- High purity cotton intended for optical cleaning (often wrapped around a stick)
- Absorbent polyester swaps for optical cleaning
- Kim wipes (may be too harsh for some optics)
Q-tips are used by many consumers but should be used with a very gentle touch. One should avoid the use of facial tissues or toilet paper.
Some solvents used in cleaning microscopes include (from gentlest to harshest)
- Distilled water
- Diluted dishwashing liquid (dove)
- Optical cleaning solutions made for microscopes
- Isopropyl (not ethyl) alcohol
One frequently recommended solvent is "optical cleaning solution L," which is made up of 85% petroleum ether and 15 percent isopropyl alcohol.
Substances that should not be used on optics include
- Anything acidic
- Anything containing ammonia (including many household all-purpose cleaners)
- Strong solvents like acetone and chloroform
The general order of cleaning is
- Blow loose dust away with a blower
- Remove water soluble dirt with distilled water on a wiping tool
- Remove oily dirt with dishwashing liquid on a wiping tool
- Solvents can be attempted starting with the gentlest available on a wiping tool
It is best to clean optics in a spiral motion from the inside out, rather than across the face. use very gentle strokes and very gentle tools.