I recommend soaking collard greens to remove the dirt or grit before cooking. To clean the dirt off, chop collards and place them into a large bowl. Fill the bowl with water and gently stir the collards with clean hands. This helps to loosen and remove the dirt. Carefully pick up the collards, put them into a strainer, and rinse them under cool water before cooking. If you find a lot of dirt floating around or settling at the bottom of the bowl, you may consider repeating the step of soaking and stirring to remove the remaining dirt.