Simplex pneumatics require special consideration when removing old
cloth and glue.  These (three tier screw on) pneumatics also contain
the valve, and pouches within the unit.  If you want to keep the
original pouches and bottom valve seats. ( these usually are in good
condition) be very careful with steam.  I  try peeling as much of the
old cloth as possible.  Sometimes it peels right off, other times most
comes off, still other times most of the cloth sticks to the wood.  On
a Simplex you   can disk sand, the sides at least.  The front edge may
be beveled on the unit side of the pneumatic.

   For steaming try a wet rag over an electric steam iron clamped in a vice.

Richard Moody