Preheat oven to 200 degrees F (95 degrees C). Lightly grease two 9x13 inch baking dishes.
Combine peanuts, nuts, wheat cereal squares, rice cereal squares, toasted oat cereal, pretzel bits, and slim pretzels in prepared baking dish. Mix together, and spread out evenly in dish.
In a medium bowl, combine oil, Worcestershire sauce, garlic salt, seasoned salt, and celery salt. Mix together, and pour mixture over dry ingredients. Place mixture into the 2 prepared baking dishes.
Bake for 1 1/2 to 2 hours, or until toasted and crispy, stirring with a wooden spoon every 15 minutes.
