This is available at Lowes for the modest price of $2.24 and with about two minutes to alter the original, you can have the best plunger I have ever used.
Modifying your new mute-
1. Place on table and with a hack saw, cut off handle to match included picture.
2. Sand smooth if need be.
3. Pick up in left hand.
4. Place in bell.
5. Play a note as you move the mute around.
If you would like to hear how it sounds, just click on MP3 below.