Delete Cutting Planes

At any time, with 3D Cutaway on, grab an existing Cutting Plane or line and drag it into the nearest garbage can to delete it.

CuttingPlaneGarbage.png 

To delete all Cutting Planes, use the Delete All Cutting Planes command from the Standard toolbar

DeleteCuttingPlanes.png 

or from View > Elements in 3D View > 3D Cutting Planes.