Musicbrainz (only add musicbrainz ID)

I am looking to automatically add the musicbrainz ID to all my albums. In the past I tagged them all with Discogs tags but 1 program i use needs the musicbrainz ID. I do not feel to go through all my albums and individually tag them again only to add musicbrainz ID. Does anyone know a work-around?

Old thread, but i have got the same problem. I only want to add the Musicbrainz album IDs to my files. All other tags should be left untouched. (Kodi/XBMC is working with these IDs!)

Does anybody have a solution?

Two apporaches:
one: edit an existing web-sources script and remove all references to other fields than the album id.

second: create an export-script that saves all tag data into an external file, use the musicbrainz web source to get all the data from musicbrainz, including the album id, then restore the old data from the external file.

Another solution:

Add a new 'Action' with the function 'Remove fields except' and add all the single tags that you want to keep. Everything else will be deleted.