Rub it in?
How often?
We cut little pieces of cotton cloth (like pieces from an old tee shirt) and fold in fours, put vinegar on it (soaked), place on wart, and tape on with medical tape. Overnight is good, and/or during the day.
Getting rid of very, very stubborn warts. Tried everything else. This is working. It can sort of eat up surrounding skin so the vinegar soaked cloth squares need to be folded to fit just on the wart as much as possible. Working on a finger and sole of foot. I read to use apple cider vinegar so I am using that, but other kinds might work just as well.