The flow from my MOEN shower valve had slowed to almost a dribble. I pulled the cartridge out last night and saw that it was clogged with more pipe leavings than I could reasonably clean without time and some CLR. Put it back in and went out to get a new one today. Opening it up I saw that it did not have the screen in it like my old one (the one on the right). What gives- is/was this screen part of the MOEN assembly at one time? This may be the original from 1961 and may never have been out of here. I can't believe that the screen came from somewhere else in my system and ended up in this cartridge. Or did somebody else stuff this in here before I moved in? Can I pull it out and clean it or pull it out and leave it out? Planning on putting a gasket kit on the old one so I have an "in orbit" spare. Thanks in advance for your answers.