Answer:
What do you throw out to use and take in when you're done?
Though easy to spot, when allowed to plume, It is hard to see, when held in a room.
What does a WW1 Trench, A Submarine and a Popular Phone App all have in common?
What English word has three consecutive double letters?
This is needed both for courage and hardcover books.
You can always find me in the past. I am created in the present, but the future can not change me. What am I?