Stain removal most often requires treatment by a cleaning professional. To remove an oily stain:  As soon as possible, sprinkle the stain with baby powder to absorb the oil and minimize the stain. When you see the powder begins to look oily, simply brush it away with a soft brush. Finally, brush well to restore the leather. If your jacket gets wet, hang it evenly on a hanger to dry at room temperature in a well-ventilated place. Remove objects from the pockets to avoid stretching the wet leather. Once it is completely dry, iron it placing a cotton cloth on it. The clothes iron should be set at the lowest setting (wool, silk) and move it quickly over the garment.