Answer:
You write on me and secrets I can keep. In places never seen. I spin like a top. Though stiff as a board I'm often described like a mop.
I can wave my hands at you but I never say goodbye. You are always cool when with me even more so when I am high!
I am always around you but often forgotten. I am pure and clean most time but occasionally rotten.
I go from house to house a messenger small and tight. Whether it rains or snows I sleep outside at night.
I am an instrument you can hear but cannot touch or see. What am I?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?