A few extra points in the epistle from Grant Chapman [160619 MMDigest].
While I mostly appreciate the points made by that post, I have a few
clarifications.  I did not mention that the pesticides, herbicides
and other-cides and multitudinous chemicals affected the tanning of
the leather.  I referred to the effects that that slurry of chemicals
has inside every cell of the hide animals.

Also I was taught 40 years ago about the rubber cement going on the
pouch after it is glued down, because there is no convenient way to
treat leather and apply suction to pull the thinned rubber into the
pores.  I can seal 88 pouches in about 15 minutes so I am not going
to worry about breathing volatile solvent.

In the 1970s I learned from the premier grand piano regulation expert,
Danny Boone, that there is one dry lubricant that is slicker than
graphite and it should be used on grand knuckles when regulating and
that is specifically Johnson's Baby Powder.  Not other brands and not
talcum powder as that is not slick.

I use it on sealed pouches because I have it readily available, it is
slick, and it reduces leather rubbing on pouch feet attached to valve
stems.  Also it glistens just like whatever powder Ampico and Duo-Art
used on their pouches so they may have used Johnson's as well.  Just
last week I purchased several large bottles of it to last for many
years just in case they change the recipe in the future.

Doug L. Bullock
http://thepianoworld.com/