Fill a small bowl with a drop of soap and 1 cup of warm water.
Saturate a small portion of your washcloth with the soapy water. You don't need to soak the entire washcloth.
Dab at the ink spot gently.
Dry the cleaned leather with your washcloth, using a dry area of the cloth.
Dip a cotton swab in isopropyl alcohol.
Rub at the ink stain gently. Make sure you are constantly turning the cotton swab -- and replacing the used cotton swabs -- so you are always rubbing a clean portion of the swab on the stain.
Continue until all of the ink has been removed.