when to replace ivories

[Mark Davidson]

Hubert liverman writes:

>I am not an ivory expert either! However I have 
>had some experience cleaning cracked ivory key 
>tops. I found that most 'blackness' was due to 
>household cooking /finger grease. A 'caveat', we 
>do not know the the thickness of the ivory, the 
>narrownes of the cracks. Are they splinter, or 
>wide enough to use a solution to clean said 
>cracks? We also do not know the quality of the
>piano in question. Please help.

All original 5'2" Knabe from the late '20s.  Appears
to be suffering more from lack of use than anything
else (no wear on pedals, hammers, keys, but 
unplayable due to most keys being - well - immobile).
Some mildew inside leads me to think some serious
humidity exposure somewhere along the way.

I guess you would consider the cracks narrow, still
possibly a lot of the blackness would clean up.

-Mark