So it seems like the food grade line is a B**** to remove, even with a burnout. So it seems that finding the barrel that had the most "neutral" contents prior to acquiring it will be the least amount of work. I read someone who got one that had sandblasting material in it. No liner and no VOC...
Thanks for the stories about people using VOC containers. I'd rather not clean that stuff out if I don't have to, but glad to know it can be done.