I wash mine in the dishwasher.
I think putting them in a sealed bag with ammonia , maybe half water? Overnight. Dont know what they are made of but it works on the grates and the wire racks. Otherwise, it is always safe to use mild dishwashing soap to remove grease. Also a rubber brush and lots of water. Also try CLR or barkerpers friend? I probably shouldn't be giving advice. I tried removing rust off my heating air vents for the ducts with ammonia and the paint came off with it. It was a disaster
After all that, check with the manufacturer on line or in your manual.
Soak in a degreaser like GP66 then run through a cycle in the dishwasher.
I scrub mine in Dawn dish detergent and rinse well.
Degreaser and then scrub with a dish soap
Top rack of the dishwasher, once a month.
Throw them in the dishwasher or soak them in ammonia in a ziplock overnight.