Answer (originally posted by @DWFII , a bespoke shoemaker): You could try this...wet the offending area slightly. Rub hard with a spoon or bone. As the leather burnishes it will seem sticky. If you persist, it will start to shine. When the whole area is polished, let it dry overnight. Then sand lightly with a fine sandpaper--300+--to lightly break the "shine." Now, get yourself some shoe cream that is close to the same colour and rub it in good. Let dry. Rub with a cloth and then brush. Apply wax over the whole heel. Brush again.
This question was first posed and answered in our Official Shoe Care Thread.
Have a question and can't find an answer? Try here: http://www.styleforum.net/t/228153/the-official-shoe-care-thread-tutorials-photos-etc