Great job on the sprouts! This cole crop can be harvested late in the fall as a good frost makes the harvest sweeter to the taste. In mild winter areas like Western Washington you can harvest all winter even when it snows as the cold keeps the sprouts fresh. Remove the top leaves closest to the ripening sprouts in early fall to encourage ripening. It is okay to leave about one third of the leaves to help the plant continue making sprouts.  Harvest from the bottom up removing the balls with a twist or use scissors. Always remove any yellow or rotting sprouts . By about October the cold weather means no new sprouts will be made so you can remove all the leaves if they attract slugs. You will have some great meals this winter, Keep growing, Marianne Binetti