Warts are skin growths caused by viruses. Different warts respond to different treatments; some go away on their own. Salicylic acid products (in the form of drops, gels, pads and bandages) can help self-treatment of many warts by dissolving the keratin protein that makes up the wart and the dead skin above it. Others can be removed via liquid nitrogen freezing or electrical stimulation. Surgery may be recommended for painful or large warts that do not respond to these treatments.