Don't think just varnish, think felt. What do they have to do the stabilize the felt hammers, to keep it from being gnawed on by insects and rodents? There is usually some under the strings, also, in some instruments. What chemicals went into that? Think mad-hatter materials. How far back does this plant go? Also, what kind of solvents were used to clean wires, pins, hinges, etc.

SRS