It looks like you have a nice even scratch pattern and you're protecting and preserving the edges and corners well. I think of patina as the very thin coating of light grey oxidation, any black spots are rust pits. The patina would disappear almost instantly with any sandpaper and even with polishing paste without much effort. What to remove is a matter of taste but I think if something is found with a nice patina and little or no pitting, it's a rare thing and should be left as is.

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