Oh Oh Oh

If I were you, do not apply any sort of heat to that stained bag
Washing with hot water, etc. etc.
Heat will set the stain to the fabric
There's a good book called
Haley's Hints
It has lots of recipes cleaning different kinds of stains, burnt pans, bathroom tubs, etc., and most using environmentally friendly products (like vinegar, baking soda, etc.)

I remember in the infomercial, they were even able to remove permanent marker from a wall