For a deeper smoky flavor, consider using smoked cheeses in addition to the Cheddar and Colby-Jack. Adjust the amount of barbecue rub to your liking, considering the salt content of your rub. If you don't have a smoker, you can achieve a smoky flavor by adding a few drops of liquid smoke to the cheese sauce. Leftovers can be stored in the refrigerator for up to 3 days. Reheat gently in the oven or microwave.