I am not sure what the case is made of but an old nurses trick is to wash with toothpaste, the white kind with as few additives as possible. it really works to remove odors.
It works on hands and other durable washable things.
PS thanks to all for the education about featherweights. me, i carried a Pfaff 1470, fabrics, cutting tools and book to class this past winter. guess there are advantages to being a big strong gal
are the featherweights valuable? i have gone to auctions around these parts where no one bids on old machines. i never have because i don't know what i am looking at.