This posting worries me.  Old glass may have a number of problems other than
being "dirty".  Glass, depending on its manufacture, is slightly soluble in
water.  The less water, the more damaging because alkalis leached from the
glass raise the pH of the solution.  The silica structure of glass is
damaged by alkali solutions and can be damaged by very strong acids.  Damp
deteriorated glass may have water filling space in the structure, causing
cracking and crumbling when the glass is dried.

Stained glass is decorated with silver stain, flash glass, and painted
decoration.  Again, these can be damaged by harsh cleaning techniques.

There is some evidence that molds and fungi cause enormous damage to the
glass matrix.  If these are present, removal must be done carefully.

There may be added problems with leading and the glazing compound.
Structural supporting bars may be corroded or damaged and no longer fulfill
their purpose.

In short, this is a job for a properly trained conservator with a
specialization in glass.  Work should be done after thorough microscope
examination.  Some of the removal may need to be done under a microscope.
The American Institute for Conservation can give you a list of people in
your region.  202-452-9545

Helen Alten
Field Services Director
The Upper Midwest Conservation Association
2400 3rd Ave. S.
Minneapolis, MN 55404
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At 05:39 PM 1/21/97 -0600, you wrote:
>On another net was posed this question: how to clean antique stained
>glass - the glass (apparently not in a design but rather several large
>solid pieces of glass) had been stored in a cellar or outbuilding for
>80+ years.  It has gotten hard "gunk" on surface that prolonged soaking
>hasn't been able to dislodge.  People there are suggesting everything up
>through treating it with muratic acid (proper respirators, etc.) to
>break down whatever the deposits are.  I don't have a clue, but I
>thought some of the list curators or others may have good ideas.  Any
>suggestions will be passed along.
>
>Also THANKS to all for suggestions for Memphis trek.  If any more
>thoughts spring to mind please don't hesitate to send them along.
>
>Linn
>
>