I can't work out a way to quickly do it with MEL, but the first question that springs to mind is how are you going to select the materials that you want to change?
If they al had a similar name i.e blinn1, blinn2, blinn3 etc then a MEL would be great; just type in the string to search for and then apply the modifications to all shaders whose names contain that string..
If however, you were going to pick them all in the hypershade then you could just open up the channel box and change all materials in 6 very short steps. I'm not able to think of a situation that would warrant all the extra coding just to save a few simple steps, here's my way:
(1) Select Materials in hypershade
(2) Open channel box
(3) Drag-select the 3 Ambient fields to the right of the name
(4) Enter 0
(5) Select Translucence
(6) Enter 0
Then you're done.. one material or 2 hundred, the only difference is the time taken to select them in the Hypershade, steps 2 to six are identical for 1 or 200 shaders.
hope it's helpfull