I found some old (very old) gun blue in my garage... and tried it out. It worked very nice. The first attempt was a bit spotty. Make sure to clean the picks with an alcohol wipe or degreaser first and let it dry. Don't handle it with your greasy fingers!
Birchwood-Casey makes some inexpensive gun blue you can buy at most sporting goods stores.
Use a cotton swab to apply. You don't need much. Do one side at a time. Let it dry. Then do the other side.
Pete
Sioux Falls
