Answer:
What can you put in a barrel to make it lighter?
Gets rid of bad ones, short and tall. Tightens when used, one size fits all.
I'm tall in the morning and short in the noon. I disappear at night but I will be back soon.
What goes around the world and stays in a corner?
I cut through evil like a double edged sword, and chaos flees at my approach. Balance I single-handedly upraise, through battles fought with heart and mind, instead of with my gaze.
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.