Vinegar?

One of my friends recently said her vet recommended soaking their dog's paw in vinegar when he was having some sking problems (the dog, not the vet). I'm wondering now if I should try this on Fiona, who is still having some problems with her back paw despite three weeks of antibiotics and some anti-fungal medication. If I can't find anything that works, the next step will be a pricey "cat dermatologist." Has anyone had success with plain old vinegar?