Removal of dead surface skin cells is a treatment for several types of warts.

  1. Chemicals include formaldehyde, glutaraldehyde, and podophyllin. These are relatively safe and effective, but it's not known whether any treatment is better than any of the others.
  2. Cryotherapy freezes the wart by spraying (very cold) liquid carbon dioxide or liquid nitrogen on to it. Liquid nitrogen is used to freeze large warts. It's available at hospital skin clinics and some GP surgeries. A sore blister develops, followed by a scab, which falls off a week to ten days later. Larger warts may need several treatments, with three to four weeks space in between.
  3. Surgery has been used when chemical treatment fails, using a curette (small sharp instrument) to scrape the wart away. Surgery often leaves a scar and there's a danger of spreading the wart virus, so cryotherapy has become more popular.