I have noticed
 that machines with either residue (pot or cigs) don't tend to
 have mice live
 in them when sotred - I tried this by putting a bag of
 tobacco (cloth bag)
 inside and purposely left a filler plate off - no mice. The
 machine without
 had all sorts of acorn shells, poop, nesting materials, etc though. 
Great tip, thanks, the old IBM 716 Line Printer was *full*
of that; had I known I could stick a pack of Viceroys in
there to cure it, I might not have dismantled it...
-dq