I wholeheartedly agree with Bruce Clark's comments on the ease of
working with animal glue.  It is extremely easy to remove, with
a bit of care and patience.

I use all sorts of different heat weapons in my arsenal of restoration
tools.  A couple of handy weapons are a hot air gun and an electric
soldering iron.

The flat iron has proved to be a most useful tool when removing
pneumatics from deck boards, although it will cause the wood to bend
slightly.  This can be easily remedied by reversing the bent boards and
ironing the pneumatic wood bases flat again.  Sometimes the warmed wood
may need to have a weight placed on it as it cools to assist it to
regain its shape.

Perhaps the best thing to be said about using animal hot glue is that
the process is reversible so if it goes wrong you can just wash it off
with hot water and a cloth and start all over again!  A modern
synthetic glue would not allow this without some damage occurring.

Using hot glue has many advantages and very few disadvantages.  It is
also an original means of gluing so when you use it the restoration is
authentic in the way of the old craftsmen who originally built the
instruments.

Bernie Brown