I think you have this backwards.
YOU DO NOT WANT TO DELETE THE ORIGINALS. Let me repeat that. YOU DO NOT WANT TO DELETE THE ORIGINALS.
Most people do not export every single photo and then leave them there sitting on the hard disk. Why? Because they export the photos AS NEEDED, make use of the exported photos (e-mail, web, print, other), and then when the export is no longer needed, they delete the exports (knowing that you can reproduce the exported photo EXACTLY by exporting again).
In this way, you have only a single copy of your photos on your primary hard disk (of course, you need backups of your photos and catalog file on a different hard disk).