My grandmother used to put crushed charcol in a womans ankle high stocking and stick it into all the kids sneakers. We also used a bunch of charcol to deodorize an old refrigerator. It actually works pretty well.
That is for the shoes anyway.
Have you soaked your feet in h202 and Sea Salt and baking soda? There has to be some fungus somewhere.
Try coconut oil too. Mix some coconut oil with oil of oregano (melt about a 1/8 cup oil and add about 3 drops of OO) Rub this on your feet morning and night.
That's all I can think.
Since your feet are a path of elimination, perhaps there is something amiss inside?