You can take them out of your oven and soak them in the bathtub for a few hours in warm soapy water. Dawn dish soap is good. Take a kitchen scrubber pad and wipe them down-there might be a few areas you have to do some light scrubbing on, rinse, and stand up in the tub to dry. They should look just like new. Mine always do!
I take outside and use Easy Off oven cleaner, then hose off . Use a scrubby for stubborn debris.
take them outside put on top of tarp spray with blue can easy off scrub with green scrubber sponge rinse with hose. if you don't have outside area do it in the tub oven cleaner won't hurt tub just do half at a time to protect tub surround unless it's all tile or fiber glass. put a towel in bottom of tub so you don't scratch it with racks,steel wool,SOS,Brillo pads
Here is one way: https://www.hometalk.com/28053516/cleaning-oven-racks-in-the-bathtub
Last night I cleaned my oven door with a mixture of salt and dishwashing liquid (the grease remover brand). Worked well. Like said above, outside on a tarp would cut down on the mess.