What worked for me (it was on my toes, had a few ones and they started multiplying fast, had to act fast):

Apple cider vinegar. You soak a little piece of toilet paper with it. You band-aid it in contact with infected zone. Sleep. In the morning you take it off. You'll quickly notice the roots get burned by the vinegar (they get all black). Repeat day after day. At one point you'll be able to just rub it off.

100% natural, almost pain free, cheap.