Guidelines for Good Maintenance of Laboratory Biological Microscopes
① Biological microscopes should be placed in dry and clean rooms to prevent mould growth on optical components, rust formation on metal parts and dust accumulation. After use, place the microscope back into its cabinet or cover it with a glass cover or plastic sleeve, and store desiccants together with it.
② Do not disassemble any components by yourself. Insert an eyepiece cap or cover the eyepiece opening to stop dust entering the tube. Never touch or wipe lens surfaces with fingers. If dust appears, first brush it off gently with a soft hair brush, then wipe with a soft lint-free cloth or lens tissue slightly moistened with xylene or petroleum ether. Take care not to scratch the lens surface. If mild mould cannot be removed by lens tissue, gently clean it with a cotton swab dipped in a mixture of 70% ethanol and 30% ether.
③ Biological microscopes must not be stored together with corrosive acids, alkalis or highly volatile chemicals, otherwise corrosion will occur and service life will be shortened. As a general rule, a coverslip should always be used when observing liquid specimens. If the liquid contains corrosive substances such as acids or alkalis, seal the periphery of the coverslip with paraffin wax or vaseline before observation. Special caution is required for microscopic identification of traditional Chinese medicines where such reagents are frequently used and full sealing is impractical; prevent liquid from flowing onto the stage and especially from touching the objective lens.
④ Do not expose the biological microscope to direct sunlight, nor place it near stoves or heaters. Extreme temperature fluctuations may cause delamination, deformation or damage to lenses and mechanical assemblies.
⑤ Only the outer surface of the contact lens may be cleaned. If the contact surface is contaminated by chemicals, wipe it promptly with lens tissue slightly dampened with lens cleaning solution (ethanol is not permitted). If the rear side needs cleaning, use a soft brush or rubber bulb blower to remove dust.
⑥ Turn the coarse and fine focusing knobs slowly to avoid crushing the coverslip, which may damage the objective lens and condenser.
⑦ After using the oil immersion objective, thoroughly wipe off cedar oil from the lens surface. Lens tissue lightly moistened with xylene can be used, but ensure xylene does not seep into the lens assembly, as it will dissolve the cement between optical pieces and cause lenses to separate.
⑧ Keep the mirror surface of the reflector clean. Prevent water, xylene or cedar oil from penetrating it, otherwise the silvered coating of the reflector may peel off.
⑨ If mechanical parts become stiff, wipe away rust and grease with fine lint-free cloth slightly moistened with xylene (ethanol is forbidden, as these solvents attack paint). Apply a small amount of liquid petroleum grease for lubrication. Do not force knobs that are jammed, to avoid breakage.
⑩ When dirt or foreign particles are seen in the field of view: rotate the eyepiece first. If the speck rotates together with the eyepiece, the contamination is on the eyepiece. If not, shift the specimen slide; if the speck moves, it lies on the specimen. If neither, the dirt is on the objective lens. Inspect the front lens first and then the rear lens, and clean accordingly.
