Bind a key to "toggleditps" (I think thats it). Then go to the scoreboard, press the button you bound the command to and a cursor should come up, mute away as normal. Make sure you press the button to make the cursor go away when you are finished muting.
Comments
That mutes voice comm, not text.. I dunno how to mute text
The only way that I know to mute players would for a server side hook that would capture those command when they are sent and simply kill them.