Slush pile
In publishing, the slush pile is the unending pile of unsolicited manuscripts either sent directly to the publisher by optimistic authors, or sent through an agent not known to the publisher. Most are of poor quality and are rejected.
Sifting through the slush pile is the privilege of young, first-jobbing assistants to the Editors. If they find something interesting there and can persuade a Commissioning Editor to consider it, they may get some credit for themselves, especially if it is subsequently published and sells respectably.