Polariser got fungus'ed, safe to clean and re-use?

Hey guys!

So I loaned my hoya circular polariser to my friend on kind of a long-term loan, and we're both in Singapore so it's pretty humid. He left it in my roller bag, and after a few months it came back to me with fungus on the front of the filter. Nowhere else, about a 3/4 a thumb's worth of fungus that spread.

Is it safe to clean it off and use it again, or am I taking a risk like that?

Zexun

CPLs are made by sandwiching a thin sheet of plastic foil (the polariser bit) between two sheets of optical glass. IF, and it's a very BIG IF, the fungus is solely on the outside surface then it may clean off safely. Do be aware though that the glass may very well have been etched by the fungus attaching itself to the glass.

You haven't actually got anything to lose because unless you have tiny thumbs the growth probably covers a significant area. Insurance? Test your friendship by insisting on a replacement? Cry and stamp your foot? Say rude words, possibly even uncomplimentary things about your friend? Shrug & write it off? I think that realistically you will be scrapping it but do try cleaning first on that "nothing to lose" basis.

These areas of high humidity are the very reason that Käsemann filters are available (in the 1930s they were called 'tropical' filters) although they won't stop growth on the outside of course, just between the glass layers.

I wouldn't take that risk. <_<

Vixen89 wrote in post #15504433
I wouldn't take that risk. <_<

Why not? It's not usable at present or OP wouldn't have asked.

Use isopropyl alcohol to clean it, or some very strong vodka. If the vodka doesn't work, you can always drink it....

Whortleberry wrote in post #15504965
Why not? It's not usable at present or OP wouldn't have asked.

well if it was me I wouldn't use anything that develops fungus but I guess you can clean it off and let it sit in the sunlight; but I'm just paranoid about fungus...

StillCrazy wrote in post #15505002
Use isopropyl alcohol to clean it, or some very strong vodka. If the vodka doesn't work, you can always drink it....

Before using vodka to clean, after using vodka to clean or instead of using vodka to clean? Hmmm, life is full of such difficult choices.

Vixen89 wrote in post #15505011
well if it was me I wouldn't use anything that develops fungus ... but I'm just paranoid about fungus...

+1

Regards,
GEWB