Ok, have you tried Gonzo Stain Remover? I found it in my local Home Depot carpet or cleaning section. It has gotten everything out from mustard to dried-on red paint, and yes, even cola (we are non-drinkers here so I son't know about the other ingerdient! LOL.) I have at least 4 bottles on hand for anything! Once my dad saw me use it and he ran right out to Home Depot and bought himself a few bottles!

It comes in a white bottle with a red lid. Its not something advertised, but I swear by it.