Answer:
What get wet while drying
Used on a diamond and left on a board. It's great for a gymnast his grip to restore. What is it?
Always wax, yet always wane: I melt, succumbed to the flame. Lighting darkness, with fate unblest, I soon devolve to shapeless mess.
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.
You will find me with four legs, but no hair. People ride me for hours, but I don't go anywhere without needing to be tugged. Jerked or turned on, I always manage to be ready for work.
Iām grown from darkness but shine with a pale light. Very round I am and always a lady's delight.