Cleaning Gas Stove burner

Hi all!

Last Week after cleaning the Gas stove (not the electric coil), I applied some oil to the burners thinking that rust should not form on it. But after some time I cooked some meals on two of the burners and the burners turned brownish black. originally the color of the burner is some what Alluminium like metal.
I tried cleaning with almost all the thing. Vinegar, Lime, dishwashing liquid,cascade,baking soda etc. But I could not retain its original color.
Now my two burners seems to be newer and the other two seems to be very bad.

I'm living in a rental house. I hope people can understand my situation. Can anyone give me good suggesstion to clean up the burner stain .

I really feel very bad for having made such a big mistake. Scrubbing,soaking, scrubbing and I'm totally restless.