Sunshine & febreeze will do the trick.

vinegar.....having lived in the SOUTH for many years and even on the Med in Italy everyone knows you use vinegar to kill mold spores...it even removes the stains from cloth!

and 200watts...really....I think 25 or even 40 would be more than enough...any more than that and the heat could damage the fabric lining and destroy the glue that is holding it!

but I would skip it and spray with water/vinegar, set in sun and then add the charcoal odor eaters!

I keep a "dryer" sheet in mine when closed for any amount of time...I would spray with lysol and then wipe carefully til gone..

Car flooded years ago. I put old newspapers crinkled up in the floorboard. They did the trick. There were not any spores, yet, just an awful smell.

Try stuffing it with crinkled newspaper. Change the paper frequently. The smell will absorb into the paper. (Also, when we had a flood in this area in 1976 - farmers suggested straw or hay in the cars to get the smell out of it.) Just a suggestion, haven't tried it, but a we had a musty smell in a small refrigerator freezer, stuck the paper crumbled all around, and when you take the paper out -- the musty smell is in the paper not the freezer. No chemicals. Just a thought.

Why don't you try using Arm and hammer backing soda wash in hot water. I have a side table that is really old and stunk really bad and I washed it with it and set it in the sun and the smell went away. Just a note about mold make sure you use rubber gloves as you can get sick from it.

I have a mild allergy to mold and mildew which is why I need to get rid of it. So far the vinegar seems to be doing something. It's still damp and sitting in the sun so I won't know for a while, but I suspect there will still be some residual odors. It's a shame because I know it was a single owner and she is a beautiful little Centennial in really good shape for her age and I got her for under $200 with most of the original attachments and instruction book. The only problem is the case.

try putting a piece of charcoal in the case for awhile I keep a piece in my case all the time to keep the mildew smell away

I picked up a complete (including table), well used and very smelly Featherweight Centennial for $99 at a local charity shop in 2009. I read everything I could and the best info came from the car guys. A friend told me recently that the odor in the case is from an animal based glue used on the cases made in the US. Here is what I have done...housed it in our loft space, open case during the coldest time of winter. Bake it in the heat on the hottest driest days. After that treatment and being closed up during our humid season the mold spores reappeared. In frustration I took a bleach wipe to it and have had no problems since.

Keep several unwrapped bars of soap in the case. They will absorb the odor.