Put your curiosity to rest. The mystery of turnip greens is solved. Do not pick the bottom leaves, as these tend to be bitter and extremely dirty.
Some people pull the whole green up and twist off the roots, others pinch off just the green leaves.
For a family of four, a large brown paper sack full of greens should be picked. Put half the greens in this water and submerse up and down to get off all the sand and bugs. Do this with one handful of greens at a time. Transfer to the other sink. If greens are really dirty, a fourth and fifth washing may be necessary.