Hi,  There are a couple of things you can try to rid an instrument
of nicotine odors.  The first is to spray offending woodwork with
"Mean Green".  This liquid can be obtained from Dollar General stores.
Smaller bottles (about 1 litre size) have a sprayer on the top whereby
woodwork can be coated with the liquid.  Nicotine just streams down
the sides of pianos, jukeboxes, etc.  Wipe it off with a dry rag and
start again.  After about three applications, most of the nicotine
smell has disappeared.  You can use really great amounts of "Mean Green"
on the inside of the case.

The second step is to place a quantity of loose charcoal (two one-quart
baskets) inside the instrument and shut it up tight for a few months
over the winter.  When spring arrives the charcoal should have absorbed
all of the odors from the nicotine.

Hope this helps!

Best wishes,
Mike Walter
Buffalo, New York