I would use a machine shop grinder to grind off the rust from the top and sides. I did this with a bug that looked like it had battery acid spilled on it and was severely pitted. The base ended up a little thinner. See photo after plating. The dit contact blued steel is available, and can be drilled with a spade carbide bit. Getting it bent may take some doing as it's some spring steel is brittle and can fracture. You can get the silver contact point from Vibroplex, or simply purchase the whole dit part from Vibroplex. You can solder the silver contact on the blued steel after grinding the bluing off or press fit it in the hole but the tolerances are tight. Good luck!