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Treatment
Eventually verrucas will disappear on their own without treatment. However, this can take years so most people choose to have them treated.
Don't try to dig or cut them out.
A wart paint or gel containing salicylic acid, used every day, will help remove the hardened skin. Soak the verruca in water for a few minutes then dry it before applying treatment.
Freezing a verruca with liquid nitrogen speeds up the process by partly killing the virus and partly destroying the skin that the virus lives in. The freezing feels cold during treatment, like putting an ice cube on your skin, and sometimes feels a little sore afterwards. Occasionally the skin blisters but this is usually nothing to worry about. For small verrucas, a single freezing treatment is often enough, while larger verrucas often need repeated treatments every two to four weeks. Your GP may offer this treatment in their surgery.
Hardened skin can be safely removed using a pumice stone or emery board - do not to be too vigorous.
Tea-tree oil is well known for treating verrucas and warts on other parts the body. Another natural treatment that can be effective is to apply the inside of a banana skin to the verruca. Rub the inner skin against the verruca for a few minutes two or three times a day or cut out a piece of banana skin large enough to cover the verruca, tape it over the verruca to hold it in place, and leave it overnight.
Having verrucas doesn't mean you can't go swimming. Provided you wear verruca socks (available in different sizes from the pharmacist) you will not pass verrucas to other people and you won't get any more either.