Try Hydrogen Peroxide. All I do is poor some on the stain, let it sit then when dry your stain is already gone or at least almost gone. wash and your stain should have disappeared.. I just used it on a set in sauce stain and the stain was gone before I even washed the shirt. Hope it works for you.
I used water and toilet paper to get most of it off
Try the new Tide laundry detergent, its suppose to work on set in stains
What can I do to get a chocolate stain out of a tee shirt, I have put spray and wash on and it came out of the wash still there?