How to delete converted dng files

I have nearly 100 converted dng files lodging in my converter and can find no way of clearing them out.

I have a Panosonic Lumix G5 that produces DNG files which I convert to RAW using the Adobe DNG converter.The problem is, once I have converted them, they remain in the converter so every time I convert new files, the old one's are converted all over again!

How do I get rid of the already converted old ones please?

RonB