Users of small iPods, or those running feverishly low on disk space on their iPods may be disappointed to find that once they've used Clutter to add album covers to their collection, they no longer have room to synchronize their music. This is because the Album art is contained within the ID3 tags in the MP3 files.
Fortunately, there's a quick and easy fix to remove any and all Album artwork from your MP3s, without destroying your songs. In iTunes4, under the Advanced menu, is an option called "Convert ID3 Tags." Simply select the song(s) you want, and click on Advanced -> Convert ID3 Tags. This will pop up a new window allowing you to reformat the ID3 information within the MP3s. This does not affect the song.
I selected ID3 Version 1.0, which kept all of the relevant song metadata, and subsequently removed any and all artwork from the song, allowing me to reclaim back my disk space. This worked because ID3 V. 1.0 doesn't support embedded images. Running this on a bunch of songs I have did not seem to destroy other iTunes metadata such as Last Played, Play Count, and Ratings.
[robg adds: This is an alternative method to the previous hint Export album artwork from iTunes. Personally, this is also why I like Clutter -- I don't use it to import the artwork to iTunes, I just let Clutter download and display the album covers itself. I believe Synergy will do this as well...]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030524224721121