Hiding and deleting lights and grips

Delete a light

To delete a light permanently:

Select the light to delete and press the Delete key (or select Edit > Delete)
Right-click on the light icon in the Lights interface or Organizer, and select Delete from the menu.

Hide a light

To hide a light and remove its illumination from the scene:

Hide the 3D “grip”

To hide the 3D “grips” of all lights, but retain their illumination in the scene:

Press Shift-L (or select Scene > Show Light Grips) to toggle visibility in edit mode.
Enter Presentation Mode (Tab).