Combine the salt, black pepper, brown sugar, paprika and cayenne. Sprinkle over the pork shoulder and rub into the meat.
Wrap meat in plastic wrap or put into a resealable baggie or container and refrigerate for 2-4 hours.
Preheat oven to 325 F.
Add apple juice, apple cider vinegar, Worcestershire sauce, liquid smoke and garlic powder to a large Dutch oven and stir.
Add the meat to the Dutch oven. Place foil over the top to create a tight seal and cover with the lid.
Roast in the oven for 4 hours or until the meat shreds easily, basting with the liquid in the pan every hour.
Remove from oven and let stand for 30 minutes.
Shred pork with forks, discarding any large fatty pieces.
Serve over buns topped with slaw and, optionally, BBQ sauce.