I have found PVC-e glue to be easy to remove.  It does not penetrate
very deeply and can be removed with gentle scraping with a razor blade.
In my opinion this produces less damage to the wood than sanding hide
glue or other methods of removing it.  Other white glues can be
difficult.

If you are using PVC-e glue and you want to make it even easier for the
next rebuilder, you can prime the surface with polyvinyl acetate (PVA)
which is used in all sorts of industries including the restoration of
fine works of art.  Good grades are suitable for priming canvases
before painting with acrylic and oil paints.

Although the PVC-e glue will stick well to it, the PVA can be removed
at any time, along with anything on top of it, although it is probably
not necessary as most adhesives will stick to cured PVA.  If you have
any doubt, try some tests before using it.

It is always nice to secure a note in the instrument with your name,
date of rebuild and any special details such as how things were glued
and how they may be undone in the future.

Best regards,
Spencer Chase
Garberville, Calif.
http://www.spencerserolls.com/