They are not "in the Converter" at all.
The DNG Converter does not import or ingest files, it merely looks for eligible raw files in the Folder or Directory to which you you aim it and generates the converted raw in the same place.
It would have been easier to help you if you had provided pertinent information, starting with your platform, Macintosh or Widows.
You can delete anything from that folder or directory just by dragging its icon to the trash in the Finder (Macintosh) or the Recycle Bin in Windows Explorer. Of course, you are really deleting the actual converted files, which boggles the mind.
Please read this FAQ for advice on how to ask your questions correctly for quicker and better answers:
As station_two said, they are just files on your disk (not in the converter), so you can simply delete the ones you no longer want.
PS - consider using a batch file to do conversion, so you can drag and drop the files to be converted - no other files will be converted.
e.g. in Windows, put this in a .bat file:
"C:\Program Files (x86)\Adobe\Adobe DNG Converter" -cr7.1 -dng1.3 -p0 %*
Thank you for your reply. I am sorry I have not got back to you earlier but have been rather busy of late. Unfortunately I do not know how to create a BAT file but would very much like to know how to do so and how it works.
After spending a large amount of time on this topic I decided to delete the converter and reinstall it so I would not have to wait whilst it kept converting all the files that had already been converted over and over again! As for the BAT file, if I learn how to create such a file which will include the DNG files I want to convert, once the converter has done its job, how do I get rid of it? Will I not end up with a list of BAT files rather than a list of individual DNG files?
Having always had an Olympus camera, I have never had to use the Adobe DNG converter so I am on virgin ground so to speak and as a very senior citizen, sometimes things take a little longer to sink in than they used to a few years ago.
Thanks once again for your help and I am sorry that I am at the moment to come to grips and understand the kind advice you have sent.
Kind regards, RonB
Before we go further, are you on Mac, or Windows?
And now that I think about it, do you really have to convert your in-camera (Lumix) DNGs to yet another DNG file?
Are you trying to open them in Lightroom, or Photoshop?, or?
The latest version of those softwares should open them without conversion.