Hello -- I'm about to recover the accordion pneumatics on my Steinway
Duo-Art.  I've researched all the literature about materials and
procedures in the original service manuals, and Kitner (and MMD of
course!) but nowhere have I found any word about dealing with the
nipples on the accordion blocks.

This is probably a simple question, but can any veterans offer advice
on safely removing and effectively re-installing these nipples when
recovering the accordion pneumatics?   I assume that they're sealed
with burnt shellac and that heat might set them free, but I'd rather
ask than experiment on them needlessly.   What's the best way of
getting them free, and reinstalling them?

Many thanks for your advice and experience!

Gary Busch