I, too, agree with the ease of working with hide glue; I've been using
it for 35 years.  However, removing it in preparation for restoration
was an extremely aggravating task until one day in utter frustration
I applied brute force: a propane torch.

To my utter surprise and delight, after passing a naked propane flame
over old hide glue, it instantly crystallized.  A quick application of
sandpaper and the old hide glue literally fell off in a dust, leaving
behind clean bare wood ready for a fresh application.

Yes, quite easy to overdo it and scorch the wood beneath, which I
quickly learned with that initial experiment.  At that time, about 30
years ago, I acquired a pencil type propane torch which I have been
using since.  Very easy to control the flame and achieve the desired
result.  Occasionally a second application is needed.

Always aware of the fire hazard, I tried numerous other techniques such
a heat gun, hot water, even steam; forget sandpaper.  None achieved the
satisfying result I get from passing a naked flame over the old glue.
The heat gun took forever, hot water and steam made for an ugly task
with uncertain results (for me).

Not being a physicist or a chemist, I'm not quite sure what's going
here, but the intense, albeit brief heat of the naked flame would
appear to cause the old hide glue to completely break down.  The
resulting dust no longer has any adhesive qualities at all.  It's
just simple sanding dust.

I have learned that old heavy bellows cloth will not always peel off,
frequently leaving behind a mix of bare glue and fabric remnants,
a mix that the naked flame treatment does not like.  So, for old heavy
bellows cloth, I now apply the naked flame and presto!, in an instant,
the old cloth peels off effortlessly.

From time to time the old bellows cloth will ignite into an open flame
of its own, so I have a pail of water handy.  Even if the old cloth
does not spontaneously combust, I still throw it out onto the open
driveway as hidden embers may spring to life behind my back.

I agree this approach does present a hazard and others will not feel
comfortable about using this approach.  But with reasonable care and
preparation, safe and incredibly quick and easy removal of old fabric
and glue is the result.  Try it, you will be pleasantly surprised.
Don't forget to measure the dimensions and span before the treatment.

Regards,

Terry Smythe
Winnipeg, MB, Canada
http://www.mts.net/~smythe/