One of my old 85 1.2 has a small bit of fungus in it. I thought the best place to have a service is Zeiss, Germany. So, I e-mailed them. This is their reply.
> Dear Mr. Wang,
>
> in case of severe fungus groth on the glass surfaces of photographic lenses
> we generally refrain from any repair attempt because of the high risk of
> contamination.
> If such a lens is brought to our benches, the spores of fungi would spread
> to all places
> including all used tools. This would be a danger for other lenses as well,
> which never
> had a fungus problem before.
>
> If you find fungus on outer surfaces at an early state, try to clean by
> yourself and separate
> this lens from others.
>
> I am sorry to give you this hard statement, but these rules have been
> decided after some
> very bad experiences in the past.
>
> With best regards
>
> Dr. Hubert Nasse
> Carl Zeiss AG
> Camera Lens Division, Laboratory
> phone  49-(0)7364-20-2846
> FAXÂ Â Â Â Â 49-(0)7364-20-4045
> e-mail    Â
nasse@zeiss.de
>
> Internet Â
www.zeiss.de/photo
Do you believe this is their reply for my 85 1.2 ?