“How Can I Clip — the Contextual Menu Doesn’t Appear and the Services Menu Doesn’t Work?”
 
Not all applications properly support the OS X Services menu or contextual menu plug-ins, especially older “Carbon” applications.  If you ever encounter an application that supports neither, you can clip using NoteBook’s Dock icon: copy the selection to the Clipboard, then Control- or right-click NoteBook’s Dock icon and choose a Clipping Service from the Paste to menu.