Mold can attach to the glass elements and casing of a camera lens. If left untreated, the mould may spread and render the lens unusable. If the mould is easily accessible, cleaning it yourself is possible. Should the mould be located on the glass inside the camera, you may want to seek out advice from a local camera store.
Mix equal parts of ammonia and hydrogen peroxide and set the solution aside in a bowl. Do this in a well-ventilated room while wearing safety glasses and a breathing mask.
Remove the affected lens from the camera. If applicable, remove any filters from the front of the lens. If you successfully remove the mould, you will want to ensure the entire lens is free of mould.
Remove any dust, dirt or debris from the front and rear elements of the lens using a cleaning brush. Use a microfiber lens cloth to clean the outside of the lens, and inspect the lens for any indication of additional mould.
Dampen a cotton swab with cleaning solution. Apply it to the lens, starting at the outside edge and slowly working toward the centre of the lens. Rotate the cotton swab as you do this to ensure a clean portion of the swab treats the lens. The cotton swab should be damp, but not wet. Continue this process using additional swabs, as needed, until you clean the entire lens surface.
Moisten one of the microfiber cloths to further clean the lens after the mould has been removed. Use a second microfiber cloth to remove any moisture from the lens. Allow the lens to thoroughly dry before reattaching it to the camera body; reattach any filters to the lens that were removed.
If the mould is inside the lens, a technician from the camera's manufacturer may have to remove it for you.