I have the exact same problem that this guy has, but I'm looking for a more specific solution. I'll summarize briefly to save you a click.
I married into a messy music library and I'm trying to clean it up. My wife has a ton of music that she made mix CDs with ages ago, and the ID3 Tags carried over accordingly. For example, she has a ton of tracks that have proper artist labels (say, "The Beatles"), and proper song labels ("lucy in the sky with diamonds", "hey jude", etc.). But the album tags are some form of "Beatles Mix December 2002".
Is there an easy(ish) way for me to re-tag them with their proper albums? It's not the re-tagging part that's hard, it's the figuring out which album songs were released on part that's hard.
And I get that any one song may have been released on multiple albums- live versions, acoustic versions, best of, studio compilations, etc, sure. I'd like to consolidate the songs into as few albums as possible, erring on the studio album side and away from any special releases or whatever. What I suspect is that her mixes contain a lot of full-length albums or EPs.
The total number of tracks that I'm describing is not an impossible amount. So even if some solution is a bit manual and tedious, I'm willing to try it. But I'll definitely need the help of a Music Brainz lookup or something to help me out. Any ideas about the best way to do this?