Knock Boxes, Knock Bins, and Dreg Drawers
A knock box is an essential implement for every semi-automatic espresso machine owner. It reduces the effort and mess of getting the spent coffee grounds out of your porta-filter. Instead of trying to dig the grounds out, you just invert the porta-filter and rap it down on the knock box cross bar to eject the spent "puck" of coffee grounds into the knock box. At the end of a brewing session you merely tip the knock box contents into the waste bin, or add the spent grounds to your garden composter!