Multi-select problem: How does the next paragraph end?

How to ripen an avocado
Place the unripe avocado into a brown paper bag.
The bag is used to trap the ethylene gas, which ripens the avocado. Make sure there aren't any holes in it!
The paper bag is just a trap.

Pick from:
1). Leave the open end open until you're ready to work on the avocado. Wash and dry the avocado.
2). Only unripe avocado can leave the bag. Soak the avocado with water.
3). Test out how much food your avocado eats and how long you should allow it to ripen. If the avocado turns brown, it is overripe.
4). If you can devise some other mechanism that will trap in the air in the same way, great! That can be used, too. Your grandma might tell you to store it in the flour bin, but you may have to settle for the empty mcdonald's bag.
4).