I'd use an oxygenated powder like Awesome Orange or OxyClean and water on an old t-shirt and scrub it in. The more water the better. If you can take it outside to air dry even better.
Try sprinkling the stain liberally with Borax. Spritz water lightly over it and let it sit till the water dries; then brush off or vacuum up. This has worked well for me.
Have your tried oxiclean? It works miracles on organic stains like that!
I've heard hydrogen peroxide works great. I've used it for pet stains with success