Answer:
I am a tale in childrens' minds. Though an illusion, I occur every night. I give them a fantasy, I give them a fright. What am I?
I am always around you but often forgotten. I am pure and clean most of the time, but occasionally rotten. What am I?
The more you take away from me, the bigger I shall get. What am I?
My days are numbered.
What gets sharper the more you use it?
A first job for many kids, this could be described as "Media Distribution Management.