I do not recommend Compound W for a wart on the bottom or plantar area of the foot. The skin is too thick and many people expect quick results. All you are doing is burning the skin slowly with a weak acid. A wart is not specifically killed by this. Warts are caused by the Human Papilloma Virus ( HPV) of which there are many. There is no known cure for this problem, often considered to be a simple nuisance. My patients would disagree with that statement as many of them hurt from the pressure.
My recommendation is to see a podiatrist or a dermatologist for further treatment recommendations.