Liquid Nitrogen is a commonly used as a treatment for people who have small numbers of solar keratoses. This is also called cryotherapy or cryosurgery. Liquid nitrogen is so cold that it destroys tissue. A solar keratosis can be easily sprayed with liquid nitrogen. It is destroyed and then falls off a few days later. A small scab is left and is gradually replaced by fresh healthy skin. Liquid nitrogen often causes the surrounding skin to blister for a few days. Sometimes this form of treatment can leave a white spot on the skin after treatment.