If you're using v2.0, they're in the "soup views", i.e. "Albums", "Artists", etc. If you can't remember which ones they are, just type "refs=0" into the Advanced search box.

If you're using v1.0, they're in the "Unattached Items" playlist.

If they're in neither place, but are still on the empeg, don't worry too much -- the FID numbers'll be reused soon, and they'll get overwritten.