For short term use. Salicylic acid collodion is used to treat skin warts. As an acid, it can be painted on the wart, as directed by the doctor. The acid eats away at the wart, and over time, gets rid of it. Doctors can freeze warts and other skin growths, so freezing (cryo) may be faster treatment. If used just on skin growths in a few small parts of the body, there should not be long term exposure to the medication.