You can export them to a PGN file and use many chess programs to analyze and review them. Then you can delete them from the PGN file using the chess software's deletion function or manually with an editor such as Notepad.
Depending on your chess software, you can also annotate and analyze key positions or get advice on where you went wrong. There are free programs that do this, but obviously some of the paid software has great features that may not be available in the free ones.
How can one review games, then delete those that have no value as lessons.
The review part's easily done but I can't find a delete function....