When using acid or alkaline solutions to clean microscope slides, what precautions should be taken to ensure their cleanliness?

Right solvent selection: Suitable solvents should be chosen for specific materials and contaminations in slides. To mention a few; for optical surfaces it is better not to use methanol, ethanol etc as they are known not leave residues. It is always good too choose the solvents that effectively remove contaminants but do not affect surface of slide.

Avoid dry cleaning: Never wipe the optical component directly with a dry cloth or clean them with dry solvents as this may cause scratching or other physical damages. Wet cleaning must be done using appropriate liquid solvent and ensure that it is fully dried before moving on to the next step.

Utilize high quality wiping materials: Use high-quality lens paper or equivalent fabric-like substances in order to avoid friction and scratches over a slide’s surface.

Dry out well: A cleaned slide has to be thoroughly dried so as not to allow any further contamination from residual moisture leading further damage. Ultrasonic assisted drying technology may come in handy while accelerating drying process.

Prevent re-contamination: In course of washing, prevent re-contamination. For example, if dust particles intrude during the cleaning process you will have nothing but dirt again.

Regular inspections and maintenance: Even after intensive cleansing, regular checks should still be made on slides so that new contamination or breakages may never take place.

References：

1. Amanda J. Souna, John S Bender et al. “How clean is the solvent you use to clean your optics? A vibrational sum-frequency-generation study..” Applied Optics (2017). 3875-3878.

2. J. Bennett. “Dos and don’ts in characterizing and cleaning optical surfaces.” SPIE Optical Systems Design (2005).

3. Jeffrey M. Larson. “Cleaning A Microscope’s Optical Surfaces.” Microscopy Today (2001). 26 – 27.

4. J. Strobel. “Cleaning of parts for precision-optic and glass substrates before coating.” Optifab (2003).

5. C. Duke. “Lens Cleaning – Best Practices Review.” Microscopy Today (2004). 42 – 44.