Most plantar warts go away without treatment, though it may take a year or two. Freezing therapy done  involves applying liquid nitrogen to your wart, either with a spray or a cotton swab.  The chemical causes a blister to form around your wart, and the dead tissue sloughs off within a week or so. It may also stimulate your immune system to fight viral warts. Some studies show that this treatment is more effective when combined with salicylic acid treatments.