Decide how you want to smoke the brisket - whole or in pieces. Rinse under cool water. Pat dry. Trim the fat cap to ¼-inch thickness, as well as the vein that runs between the flat and the point.
Coat brisket on all sides with oil or yellow mustard. Stir together spices and brown sugar until combined. Liberally apply the rub to all surfaces of the brisket. Let the brisket rest and marinate with the rub for up to an hour until it reaches room temperature.
Preheat smoker to 225°. Add wood chips to the hopper and pour apple sauce into the pan in the bottom of the smoker. Cook for 8-10 hours. Remove brisket, wrap in towels, and place in a camping cooler for 2-4 hours.