Stained leather is another tough proposition, and in many cases there is not much you can do about it. If you are dealing with a fresh stain you need to act agressively and quickly to prevent it from setting. Simply use a damp cloth and wipe it up as quickly as possible. Stains from greasy or oily substances can often be lifted out by sprinkling powdered chalk on the area and letting it set overnight. Use a light brush or cloth to remove the powder after a reasonable time. Don't rub the powder in -- it won't help. Lighter stains can often be "hidden" by treating the article with Obenauf's Leather oil since it will darken the overall color of your leather item upon application. Again, always be certain to test for colorfastness and effect on a discrete area to make sure you are pleased with the results. Serious stains that appear to be well set may be irreparable. In this case, your best bet is to consult a local leather expert who may be able to offer some suggestions about professional cleaning options.