I use rcbs lube. And then lay out about 10 cases onto a clean rag. And give them a light spray of brake clean and then wipe the whole lot inside the rag. The brake clean cleans off the greasy/oily residue as well as the carbon residue that’s always on the neck.
As to whether you should or should not clean them, my school of thought is that as the case is firing, it expands onto the walls of the chamber and the chamber grips the case which reduces the amount of load that the bolt need to hold. And there’s also another group that will say that you need to leave them lubed, but I forget what their reasoning is on that. I’m just sharing what works for me.
