Banjo too loud when you're practicing? If you have a resonator model, take the resonator off. Inside you'll see either a square dowel through the middle or one (or two) metal rods running the length of the inside of the pot (under the skin or plastic head)
Get a piece of round dowel about a half inch in diameter, and cut it just longer than the space between the banjo rod or dowel and the head. Use some rough sandpaper or a file to shorten it so you can just fit it in between the head and rod. It should have to be forced in a bit so it will stay. Position it right under the bridge and it will cut your volume to almost nothing. You won't wake a soul up with this "mute" on.