The easiest way to remove old bellows fabric is to use heat.
Hopefully this project can be done outside, as it creates an
awful smell.

By placing the surface of the bellows on the hot flat surface, old
bellows cloth comes off easily.  An old electric iron for ironing
clothes works very well.  For removing thick heavy bellows cloth,
I use a propane gas torch.

In all cases, one has to be very cautious, as the wood can burn
if the surface gets too hot.

Bruce Clark