I continually have either a perforated Zip-lock type bag or a hand drill perforated pharmacy vial that are packed with those pleasant smelling laundry dryer sheets in my cases (replace frequently). Too, I use cedar balls or blocks in cases where I have room (sand these semi-annually). Baking soda would be good if case is unmoved, I agree, but too would have to be removed. Also, silica gel desssicant to remove moisture, as can be bagged or put in the vials as above. It is such moisture as is the big culprit! Febreeze, while good if case is left open, introduces moisture.