Using chemical cleaners is not an advisable method to cleaning a griddle. Griddles are meant to be cleaned using water and oil because the surface of the appliance enhances the flavor of the food cooked upon it. Using cleaners or soap tends to add an unwanted flavor to the food.
A food-service-grade degreaser can be used once a week, however, the griddle will need to be re-seasoned with oil before its next use. Common items to clean a griddle include a grill brick, which is used to clean the appliance daily, and a grill scrapper, which is implemented after each use.