That "gloss" coat is usually gold or nickel plating...it's perfectly fine to just use the terminal as it is.One last thing. If I were anyone upgrading to ''The Big 3'' I would also grind the surface layer of the ring terminals down(YES on both sides). Manufactures gloss coat them to make them shine, but what you want is to expose as much bare metal to metal contact for the purpose of conducting maximum power flow through the 0g wire. Century Drill and Tool 76431 Coarse Radial Wire Brush, 3-Inch