The cases, when I get to them, I'm going to have a machine shop clean them for me, heat, solvent, wash, etc. nice and pretty. This piece never had heat, had grease on it, but I figure acetone, propane torch, acetone again, clean enough to practice on.

What will I see if it's magnesium alloy? Never welded magnesium alloy, nor stainless. Tons of other types of metals in my time though.