I am planning on modding my hammer into a speed hammer by grinding down the "hook" on the back side, but I'm a little concerned about leaving the raw metal without a finish on it. My guns spend most of the time in my safe, but I would really hate to take a chance leaving it unfinished and having it rust or having rust spread onto other parts of the receiver. What finish/coating/covering could I use to protect the raw metal of the hammer? Thanks in advance for any info!