Type "/33change" and a menu will drop down allowing you to choose 12 types, 12 colors, 3 sizes or turn the particles off.
You can also use voice commands on channel 33, as follows:
/33 on_off /33 1 /33 2 /33 3 /33 4 /33 5 /33 6 /33 7 /33 8 /33 9 /33 10 /33 11 /33 12 /33 small /33 medium /33 big /33 white /33 black /33 gray /33 blue /33 red /33 green /33 yellow /33 cyan /33 magenta /33 lavender /33 rainbow /33 random
Spread: /33 spread VALUE - changes the time duration of the particles, range 0.1 - 30.0. (default size is small - 3.0, medium - 6.0, big - 9.0) The command will look like this: '/33 spread 6'