This does not seem to be working fully. I've scrapped the calluses away but I think the biggest issue is that I'm wearing construction boots for 9+ hours a day, so the fungus that I kill grows back through the day. I use tinactin powder to help soak up sweat, and am using a cream at night as well as the PP baths twice a day. I was using oregano oil and garlic to help with candida in case that was the origin, but I'm having trouble stomaching oregano oil. I will get nystatin and see how effective that is while using PP and DMSO, and report back.
There is another option of taking oral lamisil but the side effects are scary - "Common side effects of Lamisil Oral Granules include headache, nausea, vomiting, diarrhea, gas, nausea, upset stomach, stomach pain, stuffy or runny nose, cough, dizziness or spinning sensation, skin rash or itching, or unusual or unpleasant taste in your mouth or loss of taste". And I believe you have to be careful not to overload your liver with this stuff. I've used it before and it worked well but I'm much more hesitant now.
Couple of things...
1) In my experience, Lamisil oral is pretty safe when used with care. Using with care includes trying other thing first, then doing liver function tests before taking and while on treatment. One needs an accurate diagnosis, first. Lots of stuff is assumed to be a fungal infection when is not actually the case. A simple test called KOH can be done on skin scrapings to demonstrate fungus or not.
2) The problem might be hyper-hidrosis (too much sweat). In such case the best treatment is to control perspiration. Wet skin is prone to all kinds of trouble, including friction calluses and blisters. Antifungals and antibiotics don't do anything to control perspiration. Getting skin of feet to be powder-dry can be life altering for many people. Powder won't do much.
3) There is a condition called pitted keratolysis, which is a superficial bacterial infection of calluses, causing them to sometimes appear thick, moist and yellow, with an interesting aroma. This needs aggressive treatment, but some OTC products can work.
Main thing is getting a good diagnosis.