How long should I run a self-cleaning cycle on my Kenmore 790 oven?

Use a 2-hour Self-Clean cycle for light soils, 3 hours for average soils, or 4 hours for heavy soils. The self-clean cycle can produce hot surfaces and fumes, so ensure good ventilation and keep children away. Allow the oven to cool before cleaning and wear rubber gloves when manually cleaning exterior parts. (Page 2)