I have a Lunt LS60THA double stacked pressure tuned solar scope. A few days back, I noticed that it was impossible to focus the scope, no matter what I did. Further investigation revealed that the eyepiece end of the B1200 blocking filter has almost turned opaque. A picture showing it is attached herewith. I have no clue what this is. The part is not damaged, it did not fall. Cleaning it from above has no effect. It clearly looks something like fungus. Is there any way I can clean it? Has anyone of you ever faced such a problem? If yes, what is a solution? I am from India, so sending it back to Lunt is not an immediate solution for me. Moreover, I wanted to use this scope for the Mercury transit. I would appreciate any help from anyone.
Thanks in advance!