Keratolysis is the removal of dead surface skin cells and is a treatment for several types of wart. The most common keratolytic treatment of warts available over-the-counter involve salicylic acid. These products are readily available at most drugstores and supermarkets. There are typically two types of products: adhesive pads treated with salicylic acid, or a bottle of concentrated salicylic acid. Removing a wart with this method requires a strict regimen of cleaning the area, applying the salicylic acid, and removing the dead skin with a pumice stone or emery board. It may take up to 12 weeks to remove a stubborn wart.

see more at wikipedia