I use Dawn Power Dissolver on my gas stove grates, I spray them real ggod let set a few hours and then stack in sink and soak them in the hottest water I have, no scrubbing and I rinse them and dry them.
DON'T USE OVEN CLEANER IF YOU HAVE ANY KIND OF PET BIRD, IT WILL KILL THEM. eVEN IF THEY ARE IN ANOTHER ROOM.