Hi
It depends on the quality of the leather and the type of finish that has been applied. I would try some Prochem Prochem E400 Rex Rx which is pretty good for dye stains. Apply it to the stain with a terry towel and if it breaks down towel it off with another terry towel rung out in a solution of Prochem B109 Fibre & Fabric Rinse. Remember that the towels should only be damp, not soaking wet. Finally, apply Prochem E675 Leather Conditioner and buff with a clean dry terry towel. Should do the trick (dont forget to pre-test though!)