Answer:
I am Invisible Man's drink at snack time
I am the outstretched fingers that seize and hold the wind. Wisdom flows from me in other hands. Upon me are sweet dreams dreamt my merest touch brings laughter.
I have 24 keys but cannot open any locks. Sometimes loud, sometimes soft. What am I?
I start new then become old. Start clean but be one dirty. I usually start big then become little.
I belong to everyone. Sometimes make you happy, sometimes make you sad. I will never end until the day you do. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.