If you've got the time to do it burn the sucker out yourself with a Harbor Freight weed burner http://www.harborfreight.com/propane-torch-91033.html
Just hook that up to a propane tank and go to work from the outside of the drum. Go slowly until the steel is almost red. This will take about 1-1/2 hours. Then I pressure wash the inside to see what is left. I may wire brush if needed. Pressure washing really gets the dust out of the pores in the steel.
I checked on sandblasting around here and it was stupid expensive. I've got more time than money so I did it myself.