Drain Bush's Best green beans, reserving 1/2 cup liquid from can. Put beans, reserved liquid, chopped celery, onion powder, pepper, mayonnaise and 1/2 cup of the cheese into greased casserole. Stir to mix well. Dot with butter; sprinkle remaining 1/2 cup cheese on top, then spread crushed crackers over all. Bake 30 to 40 minutes in a 300 degrees oven.