I had a white jumpsuit that had gotten grease from my hubby's motorcycle on it and had tried several things. It had been washed and dried several times but still the spot remained. My mother told me what to do and every bit came out.
Take a bit of lard (NOT shortening...LARD) and rub into the spot thoroughly. Then fold the spot on the fabric over and rub together until it gets hot (you can feel the heat). Put a little dishwashing soap on the spot, rub it in and launder normally. voila! it should be gone.