In a bowl, combine all of the spices together and blend well. Now, rub all of the spices into the meat. Coat every surface exposed, making sure to leave nothing uncovered. Once the shoulder is completely covered in the spice mixture, carefully put the shoulder into a gallon bag, wrap it tight so all the excess air is pushed out, and store overnight in the fridge.

MEG'S TIP: You can at this point freeze the pork shoulder if you do not want cook it yet. Just know it takes a day or two to defrost the whole thing.