M100 footage re-use

I have a weekly show I'm trying to edit. In each show, there's a few elements that I use over and over. Those are Music and graphic open and close, as well as a selection of shots in a bin that ive labelled "cutaways". I also have a bin with 4 different titles/phone numbers. What I want to do is clean out my drives after each show has been mastered to tape, and only keep the 2 bins(cutaways and titles ) for use in the next show. What steps do I take? What do I trash, and what do I keep. ALso why do several older shows still appear on my desktop? Thanks so much for your help!