Answer:
How do you discover something that does not exist?
What is yours but only used by others?
What always comes into a house through the keyhole?
If a rooster lays an egg on the exact peak of a barn, which side does it fall?
What is the largest $ amount of change you can have in your pocket without having exact change for $1?
I stand in one place yet fill the whole room. I can be filled with molten rock and come in every hue. What am I?