How do I soak and clean a badly burnt and stained air fryer flat tray?

I specifically got stainless steel fry baskets to go in there because I cannot bring myself to trust Teflon anymore. Besides the sense of risk, it just wears out so fast it's like I rented it. I'm all stainless, tempered glass, and cast iron these days. And you can scrub the shit out of those.

Once you do get it clean, keep it wrapped in aluminum foil so you never have to worry about this again.

Scrub with wet salt and/or wet baking soda because both are abrasive.

Leave the baking soda + water gloop on the stains for maybe half an hour because baking soda cleans things, then rinse and repeat as necessary.

It depends on what it's made of. If it's still you can soak it in lye water, or use easy off oven cleaner. It'll tear apart the burn spots in the organics and leave you with bare metal.

The tricky part, is if it's aluminum. It'll actually corrode the surface. All the organics will still come off of it, but it will leave a black oxide coating on the surface. Now to be fair that Black oxide coating is easier to scrub off then the original grease carbon, and polymers, but it will leave the surface a little thinner and a little pitted. If you do it more than a few times on thin aluminum you can actually put holes in it.

The next best thing to use would be bar keepers friend which is an oleic acid powder cleanser it requires quite a bit more elbow grease but it will get the job done without hurting the metal.

Soak it in lye. Its easy to find crystalized lye labeled as drain cleaner.

Caustic soda might work cleaning oil stains.

Is it coated with anything? If it's just bare metal then scrub it with steel wool and some water, any burns & stains should come off without much effort.

If it's coated then I'd try to soak it in soapy water over night and then gently scrub. Keep in mind that anything you put on there you're probably going to eat with your next few meals so before you use any aggressive chemicals just buy a new tray.

Have you tried giving it an overnight in some Coca-Cola™️. It's one of the best, cheap cleaning supplies I have in my house.

Have you tried vinegar?