CADWorx Plant II tab: Layers > Delete Layer 
Plant menu: Utility > Layer Control > Delete
Command line: LAYERDELETE
Removes all of the entities on the layer associated with an entity that you select. For example, you can delete all the entities, such as lines, text, and so on, on layer 0. You must select an individual entity.
If you select the VIEWL layer, the software displays a warning message. Deleting the VIEWL layer deletes a block named CPM which the software inserts when beginning a new drawing. This block contains information (sizes, specification, and so on) that are used when opening an existing drawing. If you delete this layer, this information is not available for the next drawing session. You can re-enter this information.