Cook pork over medium high heat in a 4 or 5 qt. pan until fat begins to melt. Add onion and garlic and cook, stirring often, until onion is soft (about 5 min.). Sort beans and discard debris; rinse well. Add beans and epazote to pan and pour in broth and water. Raise heat to high and bring to boil. Reduce heat, cover and simmer for 2 to 2 1/2 hours (or until beans are tender). If beans are too soupy, boil over medium high heat, stirring often until thick enough. Season with salt. 6 to 8 servings.