Add broth to a pot and place over medium-high heat. While it's heating, rinse and dry the arugula.Bring the broth to a simmer, and add the garlic and arugula. Stir and cook only long enough to bring up the bright green color, about 2 minutes. Gently salt and add a little olive oil at the very end. If there is too much liquid, use a slotted spoon to remove the greens to a plate. Then reduce the liquid by simmering it longer. Add the strong broth to the greens before serving. Can be eaten warm or room temperature.