Answer:
I am black when I am clean and white when I am dirty?
It doesn't live within a house, nor does it live without. Most will use it when they come in, and again when they go out.
By Moon or by Sun, I shall be found. Yet I am undone, if there's no light around.
My first is second in lineอพ I send shivers up your spineอพ not quite shining bright I glitter in the light.
What can you share and still have all for yourself?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.