Hydrogen peroxide must be periodically applied to the affected areas until all the spots disappear. Use a small brush or a cotton swab to apply the hydrogen peroxide for a more precise application. The skin around the area to be treated must also be applied with a moisturizer or lotion prior to application so that they will not be burned by the hydrogen peroxide. The treatment can be done at one week intervals, if necessary. To prevent the recurring growth of seborrheic keratosis, hydrogen peroxide can also be added to bath water.