WD-40 Spot Shot instant carpet stain remover.
http://www.wd40.com/Brands/spot_shot.html
Regular WD-40 will regenerate a "set" oil stain in fabric.
mineral spirits on a clean cloth and dabbed on the stain followed by Tuff Stuff
Goggle it, there are many ways, Big shop Vac and "DAWN" dish detergent. (Dark carpet you can use "Simple Green" instead of DAWN)