Answer:
I am the key that is the hardest to turn
I am the place to turn when nature calls.
What is black when it's clean and white when it's dirty?
I can be repeated but rarely in the same way. I can't be changed but can be rewritten. I can be passed down, but should not be forgotten. What am I?
You cannot keep me until you have given me. What am I?
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.