Manipulate saturation / make movieclip grayscale

in the filters panel, there is an “adjust color” option… and inside of it, there is an option there for “saturation”… setting it to the lowest (-100) will turn the movieclip / whatever object you’re applying the filter to, to grayscale…

i was wondering, how would i go about this using code?

for example, if there was a movieclip on stage called “thePic” and i wanted to decrease its saturation slowly every enterframe until it finally becomes grayscale, how would i go about it?

i know how to manipulate the other filters like GlowFilter and BlurFilter through code, but it seems like there is no “AdjustColorFilter”… there is a ColorMatrixFilter, but i dont event understand how it works… please help…