To prepare the greens: cut away the tough stalks and stems from the collards and discard any leaves that are bruised or yellow. Fill the sink with water and salt, the salt helps to remove any impurities. Wash the collards thoroughly to remove the grit, 2 or 3 times, until the water runs clear. Dry thoroughly. Stack up several leaves and roll up lengthwise in a bundle, cut them into 1-inch ribbons. Repeat until all the leaves are shredded.
Heat a large deep skillet over medium flame and coat with the oil. Add the garlic and saute for 2 minutes to soften. Add the greens and toss well with the oil and garlic. Pour in the chicken broth and cook for 45 minutes to 1 hour until the greens are wilted and tender; take care not to overcook. Season with salt and pepper and serve.