Cooking food directly on oven rack
Presumably the reason you're cooking directly on the oven rack is to let the fat drip down.  If so, do yourself a favour and get yourself a roasting rack.  It's an inexpensive piece of equipment that you place in a baking pan or on a cookie sheet; the food cooks on the rack and the pan/sheet catches all the drippings.  Way better than trying to replace an entire oven rack.

And if you really hate cleanup, you can line the pan with parchment paper or aluminum foil and just throw the rack in the dishwasher when you're done.