Well there ya go, short version.
Open CM2.
Search for the offending item.
Highlight offending item.
Press Delete.
Longer and probably better version.
Open CM2.
Right click on offending item, choosing View Dependencies
View in main list.
Right click and choose View Dependent Assets.
Oops, this one's needed for blah, blah, blah, that I want to keep.
Ah, that one's used in blah, blah, blah. Don't need that. Press Delete
Do that for the stuff you don't want.
Norm