IMO, there is more than one side to a piece of brass. I like for the insides to be clean as well, even though I know such a thin layer of carbon isn't going to hurt anything, it's just my preference. I also take pride in my work. Obviously, a group of 20 going through a single hole is more prideful than a shiny case with a lead top, but I like for my work to be seen as to reflect the amount of time and detail I put toward each round loaded.