Carbona 2-in-1 Oven Rack and Grill Cleaner - 16.8 Oz Heavy Duty Degreaser for Stubborn Grease & Burnt-On Food - Perfect for Oven Racks, Grills, BBQ Grates & Kitchen Appliances

Wow - this removed 95% of the grime on my oven racks! I know it stated to leave it in the plastic bag for 8 hours but I actually left it in there for a few days and my oven racks look like new! I rotated the plastic bag around 4 times and then let it sit each time - I think the trick is to make sure your racks are coated with the cleaning material and rotating it helped. I've already ordered this again as I clean those racks about 3 times per year.