Some reported ways to keep the grill grate clean…
Pour 1 cup ammonia in a thick garbage bag, place your grate inside the bag and seal tightly... use a rubber band to seal the garbage bag... It is important you seal the bag tightly... The fumes from the ammonia is what gets your grate clean, not the liquid... If you do not seal your garbage bag tightly the fumes will escape and your grate will not get clean... Place your bag in the sun and let it sit there until the following day... Because ammonia is a toxic substance to animals, grass and plants make sure the bag is sealed tight enough that no ammonia would leak out and cause any harm to the surrounding environment...
Or another way
Whether you have food that won’t come off with a grill brush or you’re doing your annual deep cleanse, soak the grates in a mix of vinegar and baking soda... The vinegar and baking soda will work together to break apart burnt-on food…
Mix 2 cups of vinegar and 1 cup of baking soda in a garbage bag…
Seal the grates in the garbage bag with a rubber band…
Soak the grates overnight…
Remove the grates and rinse them off with water... The food that was originally stuck on the grates should fall off, but if there’s anything still stuck-on, you should be able to easily scrub off the rest…
Yet another way
Brew a full pot of coffee, pour it into a basin and then soak your grill grates… Let it sit for about an hour, give it a quick scrub and then rinse with warm water… The grate should be good as new.
Still another and green way
Wipe your grill clean without the chemical waste by rubbing an onion against the grate of the grill... the scrubbing a halved onion faced downwards on a heated grate will remove the grime and grit without requiring the hard and frustrating scrubbing... Plus, it's an affordable green alternative that won't cause putrid smells like most chemicals do… That is, as long as you like the smell of onions…
No guarantees…