Fungal infestation in Flattener - Disassembly & Cleaning

Problem:
A flattener lens exhibited fungal growth on the lens edge (colloquially known as "glass fungus").
If left untreated, the fungal growth can continue to spread across the surface of the optics. The fungus does not "feed" on the glass itself, but rather on the minerals on the surface, which are deposited either during manufacturing or during suboptimal storage.

Solution & Procedure:
Due to the existing coating, harsh chemicals cannot be used here. Furthermore, re-infestation must be prevented at all costs.

The flattener was carefully disassembled – gloves are mandatory. A small cylinder covered with a clean microfiber cloth is helpful when removing the lenses. The housing and threads are thoroughly cleaned with alcohol and dried thoroughly. The lenses are cleaned with "optical cleaning spray" and then irradiated with UV light to kill the fungus.
A check with a UV lamp shows whether the cleaning was successful and whether any residues have been removed.