Do you ever get those layers that just won’t go no matter what you try?
Even when there is nothing visible on them, you try to remove them and they just won’t go away with purge or using the Layer Manager. Don't get frustrated use the powerful Layer Delete command supplied with AutoCAD for those elements. Just type LAYDEL at the command line and you will be given the option of selecting an object on the layer or you can enter “N” to get a dialog of layer names. Use your shift key in the dialog to select multiple layers for deletion (the current layer cannot be deleted by this command so be sure your current layer is something you want to keep). Be careful since everything on the layers you select will be deleted along with the layer itself. AutoCAD will prompt you for confirmation before proceeding with the deletion.
NB: For earlier versions of AutoCAD this was supplied with the Express/Bonus tools.