Avoid using a blowtorch. It is designed to stand up to everything you might ordinarily use on a firearm. About the only things I can think of that would not work are the lubes designed to bond to metals molecularly, like MolyFusion or Sprinco Plate+. I would expect a Teflon-bearing lube, like Break-Free CLP would work with it. You could use Gunzilla to clean it. That leaves a lube layer behind when it dries. You could also wax it.
