from my very little experience so far ( 3 flushes ) i've seen those little green things you are talking about...but along with that i've also seen crumb like cream stuff, chick pea like tan rocks and worms! and once absolutely nothing! so with that nothing how do you explain where the oil went? how did i pass it if i didn't see it??? hmmm.
anyway, the Liver Flush is not only for stones mind you!
i haven't had significant rock results like spock for instance (go see some of his posts and pics!), but i've had a lot of critters that im very happy to have expelled through the flush!