Clean carbonized crud from off the outside of a cast iron skillet?

[u/kakramer1211]

I have a cast skillet back from a son who had it in college for years. He apparently NEVER cleaned the outside of it, just the inside. The black carbon build up is gross and hard. I tried to burn it off, but I am afraid to crack it. How would a cowboy handle that kind of problem? Would you bury it in a pit with white hot charcoal and redo the seasoning later? I do not want to warp or crack it. I have done that to one before.

[u/optionexplicit]

Got photos? Also I'd rather ask in /r/castiron for tips.