The Featherweight Shop has a great spray that took care of a nasty odor in my Featherweight case. Often those cases develop a moldy smell from oil drip pads under the machine which needs to be changed and the pan cleaned. I did the cleaning, but the spray worked wonders on the case. It probably can't hurt to use some of that spray on the interior of the case. I used a little on a Jones hand crank case that smelled bad, probably from a similar cause, and it worked beautifully.