Welcome to Just Answer and thanks for your question. I'm so sorry to hear about the stained coat, but there is no way that you can do this yourself. Leather requires special care only a dry cleaner who is experienced in leather cleaning should be trusted to do. Be sure to tell them exactly what the stain is when you take it in. Even then, they may not be able to remove the stain completely. If it doesn't come out, you may want to ask them about dying it a darker color.