Trim pork of excess fat and cut into 4 pieces; one piece may have a bone—do not remove at this point.
Combine spices in a small bowl and rub on all sides of each pork roast piece; place all in large baking pan.
Preheat oven to 300°F. Pour cola around the pork in baking dish. Cover and cook for 3 hours. Uncover and cook 1 hour more. If pork does NOT easily pull apart with a fork, cover and cook an additional hour. Continue cooking, covered, until pork easily pull
Remove from oven and shred meat with a pair of forks. If there was a bone, remove and discard.
Toss pulled pork with your choice of barbecue sauce, if desired.