The reroll lever of my Aeolian player piano has three settings:
ReRoll, Silent, Play.  Reroll and Play are pretty self-explanatory,
but I'm curious about the Silent.  What, exactly, is supposed to happen
here?  Are both gears (play and reroll) supposed to be engaged,
disengaged?  Or is the tempo regulator supposed to lock up the air
flow?

What mine does is, as I move the lever, the play gear moves away
from the take-up spool, and a gear attached to the top roll is engaged.
Sliding the lever over, the airflow never stops, and if I put the lever
in the right position, both gears end up engaged, and lock up.  (In
fact, in moving the lever all the way over to Reroll position, sometimes
the play gear doesn't completely disengage from the take-up reel, and
locks up anyway.)

My gears (and assorted stuff) are also very dirty and sticky (someone
oiled the things).  Is it safe to take the transmission stuff out and
clean it all up?

Thanks!
Mike "Fox" Morrey