Octavia is too proud to take any food or any charity from the old woman. She feels she hasn't earned it. So, in order to make Octavia feel that she or her son has done something to earn their meal, the old woman has James take out the trash. At the time, Octavia doesn't know the trash can is empty and that this was just a ruse to get her to eat the food the old woman is offering for free. This act salvages Octavia's self-esteem because she doesn't feel the food is "charity" but something she and James earned because he took out her trash.