Andrew Grebneff wrote:

>  We are talking here about chemicals in the glass causing the SHELL to
> break down, not the glass
> itself deteriorating. Shells can become reduced to a white powder. My
> affected specimens have
> not broken down yet, but are solidly encrusted by 2 different types of
> crystals, and cannot
> possibly be cleaned... unless an ultrasonic bath could do it.

I have cleaned them with distilled water in some cases.

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Constantine Mifsud,
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MALTA.
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