Once the pretzels have cooled, you may freeze them in a resealable freezer bag. To thaw, leave at room temp or microwave each pretzel until heated through (times vary depending on microwave). If you have leftover cheese sauce, it will keep in the refrigerator for up to a week. To reheat, simply transfer to a saucepan and heat on medium-low heat. Add a few splashes of milk to get a creamy consistency going again, and once you have a creamy consistency, remove from heat and serve.