Place the crackers in a large sealable freezer container. In a bowl, mix the oil, salad dressing mix, dill, garlic powder, and celery salt. Pour this mixture over the crackers, cover the container, and invert it to coat the crackers with seasoning. Refrigerate for at least 24 hours, turning the container every so often to keep the crackers coated. Let the mixture come to room temperature before serving. Store in the covered container in refrigerator.