I keep a jar lid filled with naphtha balls ('moth balls') in the bottom
of each instrument, and haven't had any problems with mice.  It seems
that they don't like the smell.  Neither do I, but it's better than
'Odeur de Mouse'.  I just replace them every couple of months when they
need renewing.

Regards,
Bob Loesch
Lake County, California, USA
http://www.cuckoobob.com/