Hi Mark,
A more cleaner way is to setup the barcode rule so that next time you insert a cleaning tape for inventory, it would automatically be added as cleaning tape correctly.
In Admin Console, Media and Device Management -> media, righ-click the media & select inventory, check the update volume configuration and select Advance Options. Then select Barcode Rules tab and click on New button. Enter the barcode tag (depending on your cleaning tape barcode, normally is CLN), maximum mounts, corresponding media type and volume pool none.
> How do I recover from here?
Eject the clean tapes from the library and delete the volume from Netbackup. Re-insert the tape into library and do a robot inventory.