Hé 'Mushroomchan',
There might be several ways to do this, but I would prefer to do this as follows (assuming the lyrics are 'embedded' in your 'old' files):
- install plugin 'Additional Tagging and Reporting Tools'
- right click on an 'old' song, choose 'Additional tagging tools/Copy tags to clipboard'
- select lyrics, deselect all other tags (you'll only have to do this once)
- right click on the 'new' song, choose 'Additional tagging tools/Paste tags from clipboard'
(to make this even easier, you can (temporarily) create two buttons on your toolbar - right click on the toolbar/'Configure toolbar')
You might want to use 'Tools/Manage Duplicates' to have your old/new files aligned in pairs (supposing they have some tags in common with which you can order them and assuming you have both old and new files in your library)
Hope that helps,
Greetz,
b.