Place roast on heavy foil large enough to enclose the meat. In a small bowl, combine the green chile peppers, chili powder, oregano, cumin, garlic and salt to taste. Mix well and rub over the meat.
Totally wrap the meat in the foil and place in a roasting pan.
Bake at 300 degrees F (150 degrees C) for 3 1/2 to 4 hours, or until the roast just falls apart with a fork. Remove from oven and shred using two forks.
