[Vinylfantasy]

Well if all you want to do is start your library from scratch, just select all of the songs and delete.. I think that seems a little too simple, I'm not sure I understand your question...

As far as editing info/cover art for multiple items at once, select them all and then right click them and select Get Info. There you can edit the info for all the stuff you have selected. Took me a long time to figure that one out, and oh how I appreciate it now ^_^