[header] How to care for a monocular [title] Wipe off the lens. [step] A monocular has two lenses: the ocular lens (which you put up to your eye) and the objective lens. You should keep both clean to ensure maximum visibility. 
Cloth wipes are best for delicate, coated lenses, like those on a monocular. You can use a microfiber eyeglass cloth, a cotton ball, or a cotton rag.