According to the "Queen of Clean" in her book "Talking Dirty Laundry" - she recommends Spot Shot Carpet Stain Remover sprayed on, and launder in the hotest water you can use for the fabric, using a long wash cycle and adding1/2 of "washing soda" (whatever that is???) to the detergent.

Funkymonkey was right...Another solution The Queen gives is spray the area with WD-40 and wait 10 minutes, then work in undiluted dishwashing liquid and then launder as usual.

Good luck, let us know how it turns out!