Aluminum will turn dark as you use it and it oxidizes. I found out ahead of time to boil some water and speed up that process. I usually clean up with a green scrubbie pad, but very gently. If'n I was smarter, I'd clean up while the gunk was still soft.
My kettle is sort of brownish on the bottom and greyish up the sides. No worries. Just make sure to try and leave it on there.
Sometimes the sun shines in, and I close the blinds, cause I can't stand to see the light of day. I have no use for pain, but I don't mind the rain, cause I can stay inside and hear the sound.
Today I look right down, right down to the ground, there's nothing in between to break by fall. I'm blue for you, and I don't know what to do.