Answer:
Gets rid of bad ones, short and tall. Tightens when used, one size fits all.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.
What gets wet while drying?
A time when they're green. A time when they're brown. But both of these times, cause me to frown. But just in between, for a very short while. They're perfect and yellow. And cause me to smile.
Used on a diamond and left on a board. It's great for a gymnast his grip to restore. What is it?
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.