How do dies for business strike coins get prepared?
I'm looking at some BU rolls of 2009 cents I've had tucked away for years and noticed what appear to be die polish marks on some. There are several with identical markers but I just don't think they polish dies for business strike coins. So, how do those lines, in various orientation, get on the dies?
Apologies in advance for the newb question. I feel like I should know this.