Nitrocellulose is an ingredient in many products including lacquer.
Several years ago Tandy Leather sold nitrocellulose as a sealer for
leather.  I use rubber cement.

I only mentioned it was found by two restorers in the 'seventies in
Duo-Art accordion pneumatics that had the leather analyzed.  I do not
know what else was used or how they got it.  I thought a light coat of
lacquer may have been applied to the lacquer.

Years ago the rubber bumpers on cars had a flex agent added to the
lacquer so it would not crack.  Perhaps Aeolian had a formula unknown
to us today.

Don Teach