The good news with regard to removing permanent marker from a metal surface is that it is easier to remove Sharpie from nonporous surfaces. This is a guide about removing permanent ink (Sharpie) from metal.
Here are questions related to Removing Permanent Ink (Sharpie) from Metal.
How do you remove red Sharpie from a brass doorknob?
By joshnoodle from Mauldin, SC
By Lisa  10/18/2009
I haven't tried it myself, but read recently that if you go over permanent marker with dry erase marker, then rub it off with the dry erase brush both marks will be removed. Good luck.
How should I go about removing Sharpie from an old tin lunch box without removing the paint?
Do you have knowledge about this guide topic? Feel free to share a solution!