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If a lens is covered with loose dust, first try blowing
off this dust using a can of optical grade (oil-free)
canned compressed air. Be careful not to shake
the lens, or propellant may blow onto the lens. As
an alternative, use a lens brush to gently wipe off
the dust.
If the lens is soiled with greasy deposits which
cannot be blown or brushed off, use an alcohol-
based commercial lens cleaner and a lens tissue
or a lens cloth. These items are available from
camera stores. Apply the lens cleaner generously
to dissolve the grease, then blot off the lens clean-
er and dissolved grease using minimum motion.
Avoid rubbing the lens, since hard particles from
the deposit or the lens cloth could scratch the optical coatings.
If the greasy deposits do not come off with the lens cleaner, use a stronger solvent such as
reagent-grade acetone as a last resort. Gently wipe the lens surface while moving the lens cloth
to always present a clean surface to the lens. Wipe in a circular manner moving from the center
of the lens toward the outer edge. Do not reuse the lens cloth to avoid redepositing contaminants.
Optical grade compressed air