My sis, The Slightly Mad Quilt Lady put me on to this one:
Dilute your commercial dish washing powder with baking soda (soda bicarbonate).
Isn't that simple?
Sis dilutes it by half while it's in the bottle, I just put less regular stuff in the machine's dispenser and top it off with baking soda.
Green and thrifty, can't get better than that, huh?