Try putting any clear shampoo on the stain, cover it with salt, and let it sit overnight. Wash the next day. This works well on new and old stains. I shop at yard sales and fleamarkets for clothes and this has gotten alot of stains out.
I wish I could remember where I read it but I can't--Nope, the stain is there for good according to what I read. It said there is something in the cola that permanently stains unless you run it under water immediately and even then it's iffy. Now that I've said that, to heck with what they say! Try removing it anyway, just don't ever apply heat to it until you've given up completely. My favorite stain-getter-outer for pesky stuff is Dawn dishwashing liquid. It works when many other things don't. Is the jacket washable? That would be important for using Dawn, or anything else. Club soda also works on things that other stain removers don't remove. You could also try a "dry cleaning" solvent. Good luck with whatever you attempt.
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