No need to scrub, just put the oven rack in a bag and it will be as good as new.

In the bag, it should sit for about two hours. If it's very dirty, extend the time, for example, by letting it sit overnight.

After the required time, remove the grill from the bag and rinse it under running water. There's no need to scrub it. It'll be as good as new and ready to be used again.