I just had to delete more than 5,000 bib records in Millennium with only bib record #s and no review file (as far as I know there is not a way to upload bib record #s in Millennium, only in Sierra). I used the attached document to create MARC records from bib record #s using MarcEdit. After I created the MARC records, I used a load profile table to generate a review file. The load profile overlays on record ID in the 907 field.
Unfortunately, they're not in a review file. As far as I know, there are no fields or values shared by the records that Millennium could search for in order to group them together. In an ILS like Voyager, I could simply upload a list of bib IDs as a text file and isolate all the records with those IDs. I don't know how to do this in Millennium though (if there even is a way).
If they are in a review file and do not have order records attached, you can use the delete records function (in Cataloging). If anyone out there knows how to batch delete order records, I'd love to know!
In order to delete order records, you need to place the order records in a review file. You then can use the "delete records" function to delete them.