I'm definately no expert, but I was able to get more of the orange out with a good hot burn, a wire wheel on an angle grinder, and then a disk on an angle grinder (only needed for the bottom). Here are pictures of my build:
Food grade barrel. Had corn syrup in it. Tan food liner.
Burning 'em out!
Got most of the liner out.
Used wire wheel on an angle grinder on the sides and was able to get it off.
Painted with high temp grill paint.
Used an angle grinder with a disc on the bottom.
Charcoal racks wired up.
Didn't get a pic in time, this is about half eaten. LOL!
Thanks for a great forum!