If you are holding the liver, looking around you will find a green little oval thing attached to it. Cut that one out very carefully. Anyway broke it several times myself, and after letting some water on it, had no effect, so I already don't worry about it ruining the meat so much.
Got my old rooster killed by my overy rightous dog for fighting too much. He didn't make much damage, killed him fast, so we ate him anyway. He got bruised on one wing, and was also green, so dont worry about it.