If you need to clean this part, follow the instructions described in C.0., and C.1. respectively. If the part is cleaned, let it be. If the part is not clean yet, follow C.2.
Always make sure optics are cool before cleaning.
Warning! Since cleaning an optic almost invariably involves handling it, please make sure to follow the proper handling procedures at all times when using the cleaning guideline discussed below. Optics can be permanently damaged if cleaned or handled incorrectly.
In general, optics should be inspected prior to use and before and after cleaning. It is often necessary to use a magnification device (T.5.) when inspecting an optical component due to the small size of most contaminants and surface defects. Even with a magnification device, it is sometimes useful to shine a bright light onto the optical surface in order to increase the intensity of the specular reflections from surface contaminants and defects.
Polished surfaces such as lenses should be held perpendicular to your line of sight so that you can look through the optic.
If a surface defect is located on a clean optical surface, a scratch-dig paddle can be used to categorize the size of the defect by comparing the size of the calibrated defects on the scratch-dig paddle to the size of the defects on the surface of the optic. If the size of the defect on the surface exceeds the manufacturer’s scratch-dig specification, it may be necessary to replace the optic in order to achieve the desired performance.
Please make sure you have read the initial warnings indicated with❗signs at the beginning of section C.
A canister of inert dusting gas (T.7.) or a blower bulb is needed for this method. Do not use your mouth to blow on the surface because it is likely that droplets of saliva will be deposited on the optical surface.
If you are using inert dusting gas, hold the can upright before and throughout the procedure. Do not shake the can prior to or during use. Also, start the flow of gas with the nozzle pointed away from the optic. These steps help prevent the deposition of the inert gas propellant on the optical surface. If using canned gas, hold the can roughly 6” (15 cm) from the optic and use short blasts. Wave the nozzle of the inert gas can over the optic with the nozzle at a grazing angle to the optical surface.
Please make sure you have read the initial warnings indicated with❗signs at the beginning of section C.
Webril Wipes (T.2.) are soft, pure-cotton wipers that are highly recommended for cleaning most optics. They hold solvent well, do not dry out as fast as lens tissue or cotton-tipped applicators, and do not fall apart quickly like some other wipes. The outside edges of these wipes may leave some lint, so always use a folded edge when cleaning.
For smaller optics, roll the Webril wipe into a cone with the folded edge at the point, moisten the tip with a solvent (T.8.) and use the point as the wiping area. For larger optics, first cut the wipe into three pieces that are approximately 2.6” x 4”. Fold the wipe length wise so that it now measures 1.3” x 4”, and then make a fold approximately 1” from the end. Moisten the final folded edge with solvent and use that edge to wipe/clean the optical surface. Using a pump bottle to dispense the solvent will make it easier to hold the optic in one hand while moistening the wipe with the other.