Do you ever make guacamole only to have it turn brown in the fridge? I have the solution for you. Put the avocado pit in with your guacamole and it will keep its fresh green colour.
This is my most recent batch of guacamole after two days in the fridge, amay-za-za-zing!
I think it works the same for just plain old avocado too, just leave the pit with the unused avocado and it won't turn all brown and disgusting looking.
I can't remember where I heard this tip, so I can't thank anyone. If I heard it from you feel free to take credit.