Place the crackers in gallon sized plastic zipper bag or large plastic container with lid.
Sprinkle the crackers with the dry ranch dressing mix, dill, garlic powder and celery salt. Close bag and shake to mix the crackers and the seasonings.
Open bag and pour oil over the crackers and the seasonings. Close bag again and shake to distribute the oil with the crackers and seasonings. Place sealed bag in refrigerator and allow to sit overnight.
Let crackers come to room temperature before serving.