If you have a fire pit build a fire in there and set your drum in it when it's good and hot. That's how I dealt with my last liner situation, in addition to a burnout. Worked great and got the bottom rippin hot no prob which is usually the hardest part to get clean. Oh, and do it at night so you can see it glowing- no paint/liner will survive.
UDS'-55&16, Akorn, Bar-B-Q Kettle, Drum Grill, miniWSM, cobweb-covered gasser. I'm JD.