This worked for me, and my case smelled so bad that I couldn't keep it in the house! Take the machine out of the case (you are going to be sewing with it, after all) and put a couple tablespoons of ground coffee in the case. I used a couple of the Senseo coffee packs (the one cup coffee maker size) but if you don't have the individual coffee packets, put a couple tablespoons of ground coffee in a filter and tie it up into a little bundle. Then I put the case in the trunk of my car. I left it in the trunk for a week, baking in the sun. When I took the case back in the house, there was no more smell, and just a slight coffee smell. Make sure the car is in the sun, so the trunk really heats up.
Also, if it is a black FW, there is a felt drip pad in the base of the machine. Remove the bottom and remove the pad (it is probably glued to the bottom, so remove it carefully), and glue a new pad to the bottom. Rubber cement is the recommended glue for this.
In addition, if there is any old grease on the gears, remove it with a Q-tip swab and apply new lubricant. Be sure to use the lubricant, not oil on the gears. The old grease sometimes holds the smell, so removing it and relubing the machine will help with the smell and with the operation of the machine.
You can get replacement pads and lubricant at 221Parts.com.
The smell is caused by a mold in the glue they used when manufacturing case and gluing the lining on the inside. You have to kill the mold or the smell will never go away. Some of the methods will help temporarily, but as long as there is any mold alive in case, the odor will come back.
Hope this helps.
Is your dog a blue heeler? We had one for 16 years. Sure do miss her.