I had a plantar's wart over 30 years ago...they have deep roots, and do multiply.

The Prep H would have done nothing for me...they had to be burned out (totally painless, ok?).

I am sure that in this day and age there are more advanced ways to do that...but I would look at getting it done by a medical professional. Then it's DONE.

I found some stuff on Google:

Treatment

Plantar warts usually go away on their own, but most people would rather treat them than wait for them to disappear. Unless you have an impaired immune system or diabetes or are pregnant, there's no reason you can't treat warts with over-the-counter remedies. But you may wish to consult your doctor for help. He or she may suggest a combination of over-the-counter and office treatments for plantar warts.

No wart treatment works 100 percent of the time. In general, your doctor will recommend the least painful — and least destructive — methods first, especially for children.

Common treatments for simple plantar warts
Your doctor may suggest trying these common treatments one at a time or in combination:

* Salicylic acid. Wart medications and patches are available at drugstores. To treat plantar warts, you'll need a 40 percent salicylic acid solution or patch (Curad Mediplast, Dr. Scholl's Clear Away Plantar, others), which peels off the infected skin a little bit at a time. Apply the solution once or twice each day, being careful to avoid healthy skin, which can become irritated from the acid. In between applications, pare away the dead skin and wart tissue using a pumice stone or emery board. You may need to repeat this process for up to three or four weeks to completely eliminate warts.
* Duct tape. In a well-publicized 2002 study, duct tape wiped out more warts than freezing (cryotherapy) did. Study participants who used "duct tape therapy" covered their warts in duct tape for six days, then soaked their warts in water, and gently rubbed warts with an emery board or pumice stone. They repeated this process for up to two months or until their warts went away. Researchers hypothesize that this unconventional therapy may work by irritating warts and the surrounding skin, prompting the body's immune system to attack. Today, duct tape is commonly used to treat warts, especially for children who may find freezing painful or scary. It's often combined with salicylic acid.
* Freezing (cryotherapy). Freezing is one of the most common treatments for plantar warts and is usually effective, but may require multiple trips to your doctor every two to four weeks. Your doctor can apply liquid nitrogen with a spray canister or cotton-tipped applicator. The chemical causes a blister to form around your wart, and the dead tissue sloughs off within a week or so. Freezing isn't commonly used in young children because it can be painful.
* Cantharidin. Doctors and healers have used cantharidin — a substance extracted from the blister beetle — to treat warts for centuries. Today, this therapy is sometimes paired with salicylic acid. Your doctor paints this beetle juice onto your wart and covers it with clear tape. The application is painless, but it causes the skin under the wart to blister, lifting the wart off the skin. Your doctor can then clip away the dead part of the wart in about a week. However, some doctors are hesitant to use cantharidin because it's not approved by the Food and Drug Administration for the treatment of warts.

Aggressive treatments for persistent plantar warts
If your warts don't respond to common treatments, your doctor may suggest one or more of these other options:

* Minor surgery. This involves cutting away the wart or destroying the wart by using an electric needle in a process called electrodesiccation and curettage. This treatment is effective, but may leave a scar if not done carefully. Your doctor will anesthetize your skin before this procedure.
* Laser surgery. Doctors can use several types of lasers to eliminate stubborn warts. But laser surgery is expensive and painful and may take longer to heal than do other treatments.
* Immunotherapy. This therapy attempts to harness your body's natural rejection system to remove tough-to-treat warts. This can be accomplished in a couple of ways. Your doctor may inject your warts with interferon, a medication that boosts your immune system's instinct to reject warts. Or your doctor may inject your warts with a foreign substance (antigen) that stimulates your immune system. Doctors often use mump antigens, because many people are immunized against mumps. As a result, the antigen sets off an immune reaction that may fight off warts.
* Imiquimod (Aldara). This prescription cream is an immunotherapy medication that encourages your body to release immune system proteins (cytokines) to help ward off warts. You can apply this cream directly to your warts. Imiquimod is approved by the Food and Drug Administration for the treatment of genital and perianal warts, but it's also successful in treating common warts and plantar warts.
* Other medications. In severe cases that haven't cleared with other therapies, your doctor may inject each wart with a medication called bleomycin, which kills the virus. This medication is given systemically in higher doses to treat some kinds of cancer. The injections for wart treatment can be painful and can cause rashes or itching. They're not used if you're pregnant or breast-feeding or if you have circulation problems.