Preheat oven to 275F degrees.
In a small mixing bowl combine salt, brown sugar, paprika, chili powder, garlic powder, oregano, ground mustard, cumin, black pepper.
Cube pork into three-inch chunks and season pork with seasoning mixture.
Heat canola oil in Dutch oven on the stovetop. Add pork and cook until evenly browned about 4 minutes.
Stir in chicken stock and 4 tablespoons vinegar. Cover with a lid and bake for 2-3 hours, or until completely cooked. The internal temperature should reach 145F degrees for complete doneness.
Remove from oven and shred the meat using two forks or by placing it in a stand mixer with the paddle attachment. Add remaining 2 tablespoons of vinegar.
Season with salt and pepper to taste.