Melt the margarine, oil, and bacon fat. Stir in worcestershire sauce. Add salts. Remove from heat and let stand a few minutes. In large roasting pan combine nuts, cereals, pretzels, and cheese snack crackers. Pour sauce over this and toss to blend. Bake uncovered in slow oven (200F) for 2 hours, stirring every 30 minutes. Makes 5 quarts.