Add the cereal, crackers and pretzels to the bowl of a 6-quart slow cooker. \nIn a small bowl, whisk together the melted butter and Grillville spice. Drizzle butter mixture into the slow cooker and mix gently to combine. Cover and cook on low for 2 - 2 ½ hours, stirring about once every hour to avoid burning. \nRemove mixture from the slow cooker and transfer to baking sheets to cool. Allow to cool completely before serving.