A stone that no one turns over.

אבן שאין לה הופכים

This expression is often used metaphorically to describe something that is neglected, ignored, or left untouched because it is considered unimportant or irrelevant. It suggests a situation where no one bothers to examine or pay attention to it.

Shiurim in this topic
3658. While in Africa, search for rare seforim or even manuscripts that are not in use.