Also took apart an ultra-wide zoom that had fogged up pretty badly due to the fungi. No matter how hard I scrubbed the fog refused to disappear - turns out the fungi got into the lens cement. Doomed for the junk pile, I'm afraid.
Incidentally, how do you guys clean the inner elements? I don't feel quite secure doing the same thing I do with the external surfaces; I'd imagine more resilient coating would have been applied on the outside.