Keep your parts polished and your espresso primed for the pull. Anything that comes in direct contact with your ground coffee deserves some attention to ensure it doesn't collect residue that would negatively affect flavors in your espresso. It's easy enough to forget about the little screw that keeps your shower screen in place (who even remembers the shower screen?!), but keep in mind that little screw will collect residue over time too. We recommend switching these out every one to two years depending on your daily usage. Knowing that it sees just as much exposure to ground coffee and used pucks from espresso, give your shower screen screw the attention it deserves and pop in a little replacement now and then.