When I have a stubborn stain, I don't put the item in the dryer until I have gone through my entire "arsenal" of products.
Stains have different bases, so the cleaner has to be one that takes care of that base. (I don't know if I'm wording this the right way). For an oil-based stain, you need to use a degreaser, for a protein-based stain, you use ... you get the idea.
Anyway, my arsenal includes Hydrogen peroxide, rubbing alcohol(!), Z-Out, Oxyclean (love this one!), bleach, Shout, Degreaser, Shaving Cream (!), and maybe some other stuff...
I keep trying different things until the stain comes out. I once got a terribly stubborn stain out by soaking the item in Oxyclean for two days. I have had some mishaps, where the treatment area lightened up more than the original product - so sad, but the item was already compromised!
This question (stained baby clothing from long term storage) was asked before and there were several people that recommended soaking for several days in Oxyclean. I tried that and that's how I got the stain mentioned above out.