Hello Arthur,  I have found the easiest way to remove old bellows
fabric (from the exhausters and reservoir/s) is to peel the old fabric
back by hand.  If that proves difficult, you can carefully apply heat
with an iron to loosen the old glue.  Sometimes it is of benefit to
lightly scorch the old fabric with a butane torch (carefully, so as
not to scorch the wood, or yourself).

Finish with either a belt sander with 80 grit paper, or preferably
a bench disk/belt combination sander which I find ideal for most
pneumatic and bellows refinishing.  Don't sand the wood to a fine
finish as this will inhibit the new hot glue from adhering properly
to the wood.

Hope this helps.
Paul Brennan