Dust is the most common contaminant and can usually be removed using compressed air. If more cleaning is necessary, hold the lens in lens tissue and apply a few drops of reagent-grade isopropyl alcohol, reagent-grade acetone, or lens cleaning solution.
After blowing off dirt and dust with compressed air, the Drag Method of cleaning can be used to remove fingerprints or other contaminants. In the Drag Method, lens tissue saturated with reagent-grade isopropyl alcohol or reagent-grade acetone is slowly dragged across the surface. If done correctly, the solvent will evaporate uniformly without leaving streaks or spots.
Filters can be cleaned using the same methods as lenses or mirrors. The preferred method is to use compressed air or an air blower to remove dust.
Special care must be taken when cleaning gratings or wire-grid polarizers. Because the grooves are very tiny and delicate, the Drag Method is not recommended. The only recommended cleaning method is to use compressed air or an air blower to remove surface dust. Avoid methods that require any direct contacting of the grating surface. Ultrasonic cleaning should not be used as it may separate the grating surface from the glass substrate.
De-ionized water rinse, followed by a forced air drying. Wipe gently with lens tissue soaked with methanol, followed with a forced clean air or nitrogen drying. Note: Holographic diffusers are resistant to methanol and methylene chloride.
View Cleaning Optics for more in-depth information.