I ran a bunch of nickel plated brass through my carbide 9mm sizing die. Never had a problem before but this batch of 2500 was unusual in that it had turned a gray color after cleaning in citric acid (it’s that purple lacquered Winchester training ammo), and there must have been some flaking and nickel deposition on the die because now I’m getting vertical scoring on the cases.
So, what’s the best way of polishing off the deposits? Rouge? Flitz or JB bore paste? Is a carborundum containing valve grinding compound too aggressive?
All suggestions and comments welcome.