I don't have a color spritzer, but I use my aqua painter. Press your classis ink pad down in the center so you get ink on the lid. Then ink up the aqua painter and tap it over your index finger so the ink splatters on the card stock. I hope that makes sense. I get great results doing this.
Or you can do it this way, as illustrated in Kurtis's tutorial found here:
http://www.stampinkub.com/tutorials/...s/speckle