FOUND! A book is now hiding in Boulder, Colorado United States

Hidden on: 05/14/2019

Title: Book Scavenger

Author: Jennifer Chambliss Bertman

Tracking Number: 8558

Location: Admiral Arleigh A. Burke Park, Boulder, Colorado United States

Clue:

When you want me you throw me away and when you are done with me, you bring me back.
What am I?