Pull the plunger 3/4 of the way up and spray some water on to it. The water will pool on the top of the plunger, and when you pull it the rest of the way up, it travels through the screens and removes a good deal of the grounds stuck to it. Pull it fully out, hold it sideways and spray the rest of the grounds stuck on the underside into the container. Take it outside, swirl it a couple times, and launch the grounds onto the lawn. Go back inside, take the plunger apart and spray the last few remnants that were trapped in the screens.