I am going to poo-poo the effectiveness of an ozonater for odor elimination. I have a small one that I bought to combat the musty smell inside an old guitar case, and the '57 guitar that lived there for a long while.
I have the below pictured ozonater. Have used it in the closed case at least a half a dozen times for hours at a time, and even over night. Initially it seemed to work a bit, but only knocked down the strength of the smell a bit. Used to be you could smell this 20 feet way, now its perhaps 15 feet.
I have used this in a guitar shipping box, with the guitar inside the box, with what I will term "limited success".
With a musty smell I think one needs to approach the problem as one of "source control", and target killing the mold or spores or whatever it is that results in the odor. So far the best I have found is lightly spraying Lysol into the case, and I will do this on and off. I don't want to saturate the lining, but just give it periodic treatments. I haven't got the stones to do this inside the guitar yet, but need to do something.
