I would never, never, clean the face of my cylinders with anything abrasive. Scotch brite and brasso is some of the most abrasive polish we used in the Marines to put a smooth finish on brass prior to starting to polish brass. I don't even use a pencil eraser.
Nothing abrasive because you want the face of the cylinder to remain flat and true with the end of the barrel! You will eventually and slowly increase the barrel-cylinder gap.
I use some stuff called NS 100 PT
made by
Brulin & company
Indianapolis, in 46206
It smells like orange juice and take the lead and powder flash of the face of both ss and blue guns with out messing the finish...