Cooking foods like pizza directly on the oven racks can create a crispier crust. Unfortunately, when we do this some of the cheese can melt off onto the racks and get them dirty, or baked dishes can overflow onto your racks. Some ovens have a self-cleaning feature that will get the oven racks clean overnight. Most people, however, must clean the oven racks by hand. There is a method that you can utilize that will help you get your racks clean without spending hours and hours scrubbing.
Place a towel on the bottom of your tub. The towel will protect surface of the tub from the racks.
Place your oven racks on the towels.
Fill your bathtub with the hottest water possible. You need to completely cover the racks with water.
Pour a capful of laundry detergent and a cup of baking soda into the water while the water is still running so that it disperses naturally.
Let the racks sit in the water for eight to twelve hours. If you start soaking the racks at night, they will be ready for easy cleaning in the morning.
Rinse the racks off, and use a toothbrush to get any stuck-on food that is caught in hard-to-reach places. Rinse again, and let dry. Place the racks back in the oven.