Remove the membrane from the back of the ribs. Just slide your fingers around the sides to loosen it up and rip it off, or make a slice on the back and peel it off.
Pat the ribs dry with paper towels on all sides.
In a small bowl, stir together the ingredients for the dry rub. Then rub this mixture generously over the outside of the ribs to coat.
Put your ribs in the crockpot. Drizzle on 1 1/2 cups of barbecue sauce, reserving 1/2 cups for later.
Cook on low for 8-10 hours. The more racks of ribs in the crockpot, the longer you'll need to cook them.
Gently remove the racks with tongs, and lay them out on a foil lined baking sheet. Add the reserved barbecue sauce on top with a basting brush.
Place the baking sheet of rib racks under the broiler, and broil for 3-5 minutes or until the barbecue sauce starts to bubble and caramelize. *Alternatively, after basting with barbecue sauce, you could wrap them in foil and throw them on a high heated grill at 500 degrees for the same effect. Grill them with the lid closed for 3-5 minutes, or until the sauce starts to bubble and caramelize.