That chat with an old timer about lens fungus cleaning

Ran into this retired repair guy named Chuck at a swap meet last Sunday. He told me he used to use a mix of hydrogen peroxide and ammonia for stubborn fungus, said it broke down the spores without hurting the coating. I always just used alcohol wipes and hoped for the best. Tried his method on a beat-up 50mm I had sitting around and it cleared up way better than I expected. Anyone else got weird solvent tricks they swear by?

2 comments

2 Comments

the_miles12h agoMost Upvoted

Hold up, I gotta push back on this one a little. Mixing hydrogen peroxide and ammonia sounds like a fast way to eat through lens coatings if you're not careful. Peroxide is a strong oxidizer and ammonia is a base, that combo could fizz and cause micro crazing in the glass over time. In my experience, most fungus lives on the outer elements or near the edges, and alcohol wipes with a little patience usually do the job without risking anything. Chuck might have been a repair guy, but that doesn't mean every secret recipe from the 80s holds up to modern lens coatings. Your mileage may vary of course, but I'd stick to the gentle stuff and avoid becoming a chemistry set.

the_shane17h ago

Oh man, yeah, I've messed around with hydrogen peroxide on lenses before too but never thought to mix it with ammonia. Chuck knew what he was doing. I usually do a drop of dish soap in warm water with a q-tip for the real stubborn stuff, then follow up with 91% isopropyl to get rid of any leftover moisture. The trick is to not scrub too hard even if you want to, fungus can etch the coating if you're not gentle.