Hide glue, burnt shellac and egg whites.  Okay guys, some of us were
wondering if, way back when, they really were sealing pouches with
rubber paper cement or PVC-E glue or Dow Corning 111.  It was
refreshing to hear that they didn't seal them at all or at worst used
something as old fashioned and profound as hide glue and shellac on
everything.  And egg whites, but even that, maybe rarely.

Could it be they tested the pouches with a bubble jar before they even
glued them in, for, say, the Apices, reproducing pianos, etc., maybe?
For some of us, maybe even wanna be purists, what a breath of fresh
air!   Gratis to the other Robert of Roberts Restorations!

Sincerely,
Robert Leber