You can also manually delete the .wav files in the "c:\documents and settings\all users\nch swift sound\scribe\done" folder.
I have found that scribe tends to "forget" to delete files sometimes. It is not reliable when it comes to removing the "done" data files.
Also, I am not sure, but I believe that you need to leave the .txt and .dat files as pointers for completed work. The .wav files can be completed freely and, as these are the only files taking more than 1k of space, are really the only ones that must be removed.