Hi All,  I have a few pieces of leather that have been around for at
least 20 years.  They are all in fine shape.  My 'secret' for keeping
things 'fresh' is reducing their exposure to 'air'.  This is easily
accomplished by putting the materials in an air-tight bag (like
Zip-Lock) and then sucking out as much air as possible.  I do this
by mouth.

As you are closing the seal of the bag, pinch the bag such that you
create a small opening at the trailing edge.  Then simply suck out as
much air as possible and finish sealing the bag.  I also use the same
technique for foods before they get placed in the freezer or refrigerator.
It's truly amazing how damaging air is to food, or anything else that
is organic (when stored away for future use).

By the way, I do not put the leather in either the freezer or the
refrigerator.  It just sits on a shelf in my shop...

Bellows cloth is another story, and I agree with those who say 'use it,
or lose it'.  All bellows cloth stiffens with age, but storing it in
a partial vacuum and keeping it away from sunlight will help it last
longer.

Side note: I'm still amazed that the original striker cloth on my 1917
Lauter-Humana is still extremely supple.  I really wish someone could
find out exactly how the cloth was manufactured.  It is by far the
best, or longest lasting, cloth I've ever encountered in a circa 1920's
player piano.

Musically,

John A. Tuttle
Player-Care.com
Brick, NJ, USA