First rule of working with musical boxes:  Don't take it apart with
tension on the spring.  Not letting down the spring (and also taking
care to remove the Geneva stop before letting down the spring) causes
more damage to musical boxes than anything that could be imagined.
If you don't know what it means to let down a spring, either leave
it alone or consult with someone very knowledgeable.

Oiling musical boxes: use only special clock oil.  Cleaning bad oil
gummed up enough will make you understand why.  Obtain oil from a clock
supply shop or the internet or Nancy Fratti of Panchronia Antiques.

Musical combs: made of tempered steel.  First the steel (raw tool grade
steel) is shaped to the proper dimensions.  I don't know the calculations
for which note is caused by what dimensions but the items that play are
length, width, thickness of the tooth and weight (adding a lead weight
to the end to make a deeper note -- called a resonator).  Once shaped
correctly, the damper anvil pin holes are drilled; assuming that the
note is a tenor or bass note, it will need a damper to stop extra
vibrations before it is played again.

Tempering the steel is performed by first heating the steel to red hot
(bright cherry red!), dousing it in oil/water, polishing it to clean it
so you can see the color, slowly heating it until the color changes to
purple (called also blue steel).  This is the process in tempering
steel for a multitude of purposes, in this case you've created a set
of springs with a harmonic vibration relative to the dimensions and
weight.  You can add weight by attaching lead to the end of the tooth,
or even a small amount of soldier.

The width at the end of the tooth and the thickness at the middle
have alternate effects on the pitch as well (removing from the width,
I believe, raises the pitch while the thickness in the center will
lower the pitch I believe, but I always check this when I'm tuning
a tooth as I am never sure!).

That's a basic primer on music boxes.  The best rule is if you're not
sure, then leave it to a professional.

Eliyahu Shahar