iTunes: Purchased Songs on iPod not in iTunes ...

[Hrothgar]

I'm going through a long process of re-ripping my old CDs to upgrade from ACC to ALAC. As I do this, I delete the old ACC files. When I synch my iPod, sometimes I get a message that there is purchased music on my iPod which is not in my iTunes. I assume that this is an old album I downloaded from iTunes but replaced by ripping from a CD -- and I deleted the old version. But is there any way I can get a list of these songs before I decide whether to delete them?