I've always used Fuller [Fuller Pre-Laundry Stain Spray Spray][1] to remove any grease related stains from clothing. This stuff excels at black grease type stains, and will magically remove most stains that you run across. It was originally recommended to me by relatives that live on a farm, and always have stains like these to get rid of. They bulk order this stuff by the box.
[Fuller Pre-Laundry Stain Spray][1]
[1]: http://www.myfullerbrush.com/stains.htm