I remember Ming's tumor/paw very well although I'm sorry that I was off my computer when you posted your new question about it/her.
I'm glad that you had Ming seen by your vet and can't say that I'm terribly surprised that they suggested surgery.
I can also understand why you might be reluctant to do so.
Unfortuantely, I don't think there's much that you're going to be able to do about the odor which is most likely secondary to infection or emanating from the mass itself (especially if this is cancer). Keeping it clean with dilute betadine should help, of course. Antibiotics might help although they don't in every case.
Cancerous masses tend to have an odor all their own when open to the air and exposed like this mass is...even though she's wearing a boot (which is an excellent idea by the way). I've never found anything to be effective in masking this odor.
Since you're treating it topically, I do have another suggestion to make in addition to what you're using: Honey has been used on wounds for a long time but has received new interest for its healing benefits. But all honey is not created equal: medicinal honey is the best. Medihoney or Manuka Honey are products that would be good to use. These are available on the internet but are expensive. I don't expect them to heal the the mass, of course, but it may help slow down the progression and who knows? Perhaps it may help with the smell.
I'm sorry that I can't be more helpful but I'm truly glad to hear that she's doing as well as she apparently is doing. Deb