I just scoop out as much as I can with a spoon then I put some water in it to loosen up any grounds that are still stuck. I have a little plastic cup that I cut the bottom out of and glued a French press filter onto after plugging the hole in the middle, so the water drains out into the sink and I can whack the cup on the inside of the garbage can to get the grounds out. There are usually just a few left after a couple of whacks and I don't mind washing those down the sink.