idea #1

most songs repeat the same pattern throughout.

If you can map out the chords and find a wordless section with the same chords as the section where you want to eliminate the words, you should be able to cut a snippet of the wordless section and paste it over the section with lyrics.

If you run the song thru the ACW to line up the tempo of the MP3 with the tempo of the RB project, it will make it easier to select the exact section you need, and paste it exactly where you need it to be.

Done accurately, this almost always ends up sounding better than the results you get by trying to remove lyrics with melodyne.