To manage all the annotations from one place you can use the annotation manager

from the toolbar. The
Annotation Manager highlights total number of annotations drawn on the map.
Annotation Manager

It allows you to:
- Toggle the visibility of individual annotations.
- Toggle the visibility of all of the annotations.
- Delete individual annotations.
- Delete all annotations.
- Choose to see the properties of individual annotations.
- Export the annotations to a Google KML file to your computer.
- Import a new set of annotations from a Google KML file you have on your computer.
- Query on multiple annotations.
Note: Query on a Text Annotation is not allowed.