I have found that naphtha is one of the best solvents to free up
dirty, oily and gummed up components.  It is a strong solvent and
-- most importantly -- it dries very quick leaving no residue.

Regarding WD-40, I would never use this on a mechanical music piece,
clock or watch.  PB Blaster works great (better than WD-40) if
trying to free up a bolt on a vintage car but I would not use that
on any of the aforementioned either.

In addition, I only use synthetic oils and Mobil 1 is actually a very
good thick viscosity oil.  I use Nye clock oil for medium viscosity
and Nye watch oil for thin viscosity.

Kind regards,
Troy Duncan
http://www.singingbirdbox.com/ 
http://www.reugemusicboxusa.com/