‘Ghostly’ Burn Folder icons stuck in Places menu

An iMac 5,1 where I work, running Snow Leopard, had a number of unsuccessful attempts to burn DVDs. (I won‘t go into the details unless someone thinks they might be relevant.) The problem is that the Finder window sidebar still shows Burn icons for every failed attempt, under Places, cluttering it up. The original Burn Folders and data were all deleted long ago. Searching for their names in Spotlight finds nothing. Where are these files or records stored, and how can I get rid of them?