Extended Tags

I have recently inherited a bunch of MP3 files and some of the tagging leaves much to be desired.
In particular, some of the files contain some of or all of the the following Extended Tags:
CONTENT GROUP, CONTENTGROUP, STYLE.

Each of these contain the same information making two redundant.
Question is, which two and, can they be removed?
If they can be removed, how is this done?

Cheers

You can check the list of fields in the help http://help.mp3tag.de/main_tags.html

I think that STYLE and CONTENT GROUP are not standard fields.

To delete a field proceed as follows:
Load the files.
Select the files
Press Alt-T to open the extended tags dialogue.
Select the line with the field name of the field you want to delete.
Click on the red x next to the list.
Repeat the selection and clicking for all fields that you want to delete.
Finally click on OK to save the changes.

Mp3tag only treats those files where it find the field.

You might want to filter the track list before cleaning?

("$if($eql(%CONTENTGROUP%,%CONTENT GROUP%,%STYLE%),1,0)" IS 1) AND CONTENTGROUP PRESENT AND CONTENT GROUP PRESENT AND STYLE PRESENT

DD.20140529.1606.CEST

Perfect!
Thanks