I have used this for years. If your stain is stubborn keep after it. I have had good luck with treating stains even after they have been washed. This also took permanent marker off my daughters brand new sweatshirt! I got this out of a helpful hints section in my newspaper. My kids karate uniforms are the best looking whites on the floor thanks to this recipe!
Mix equal parts of the above ingredients in a container that you can shake well. I make a bigger batch in an old ammonia jug so I always have it ready. You will want a funnel or I made one from a small child size water bottle that I cut off the bottom.
I pour the mix into an old sports bottle so that I can squirt it directly onto the stain. (Be sure to mark it so a kid doesn't think it is a drink.)
I rub it into the stain or I have a laundry brush to really scrub good with. Immediately put it in the wash. I wash everything but the whites in cold and it comes out fine. If I am worried about it I will run oxiclean in the wash with it. (You figure out which stains come out easy and which are tough requiring more effort and washes.Sometimes adding oxi to the wash helps cut that down.)
This works great on kids coats around the cuffs. Mud,grass stains marker, pen, chocolate sauce and grease stains. You may want to test your fabric/color. I have never had a problem but I don't buy fancy stuff. The laundry brush really helps to get the ground in stuff like grass stains.