Any tricks out there to remove burned oil from exhaust system?

My 65 Barracuda had an ATF leak and now the new TTI exhaust pipes are blackening with burned-on oil. I am afraid to sand it off, for fear of removing the aluminized coating. Any other way to get my pipes clean and shiny again? I am referring to the TTI H pipe just rear of the tranny crossmember, I don't have headers.