It has to be made bright, the skin of this planet till it shines in the sun like gold leaf. Archangels then will attend to its metals and polish the rods of its rain.
These lines now push the idea that we must do more for our planet, that together our efforts can bring back to its former glory, full of life and vitality. Especially when the skin of the earth is compared to a gold leaf, something that is valuable, precious but quite fragile. Which is why the next line mentions the archangels because the earth needs to be cared for as if it is a divine being.