With no disrespect to Don Shenbarger, I must emphatically state that
in the case of _Stella_ music boxes, it is _critically_ important that
the discs _must_ be lubricated on the bottom side every time you play
them!

This was clearly directed by the original makers, Mermod Freres, and
in fact they provided a special oil pad applicator with each machine
for the purpose.

In my experience, most of these pads have long ago been lost, but
this does not mean the lubrication is unneeded.  The reason this is
so important is because in the system used with the Stella, the star
wheels are under constant spring loaded pressure upwards against the
underside of the disc during play, actually dragging or sliding along
its surface, hunting for a hole to be pushed upwards into and thus made
to rotate and pluck a comb tooth for a note.  This is how the Stella
system works, and so the need for lubrication on the disc surface.

I am a restorer of antique music boxes and I can state from personal
experience that the vast majority of surviving Stella instruments have
suffered broken treble comb teeth, as a direct result of discs being
played dry - with no lubricant.

What happens without oil on the disc is the spring loaded star wheels
are sliding along and get caught on some minor blemish or rust spot on
the disc surface, and the sharp point snags on this and forces the star
to start to turn.  But without any note hole in the disc surface to
raise up into, the star is violently forced _downward_ and plucks the
comb tooth _far further_ than it can flex, with the result that the
tooth snaps off.

To get the visual idea, one only needs to imagine a kid sliding down
a hill on a sled in the snow.  The ride is smooth so long as there is
snow or ice, but let that sled hit a bare patch of ground or a tree
root, and it will give the rider a tumble!

Don's advice of avoiding lubricants is correct for _most_ music boxes,
but not for Stellas. A pad of cotton, or an old record cleaning pad
works perfectly for applying a very thin, even coating of oil to Stella
discs.

As for WD-40, my experience is that it is not good for this purpose as
it forms a gummy residue in short order.  WD-40 is best for freeing
sticky things, but not for any use where the lubricative quality needs
to adhere for an extended period of time.

Reg Smith - Sublime Harmony Music Box Restorations
Gainesville, Georgia