Clean Up MSCONFIG

How do I removed old, useless entries (not programs) in MSCONFIG’s “start up” tab? There are a bunch of entries from programs long uninstalled. Using 4 regestry cleaners did not help. Can you?
I am not looking to disable programs starting up, but to remove the left over entries of programs in the start up tab. For example, I do not need 7 entries of unblocked “AOL Tray” boxes. I need to remove these entries themselves.