I can understand you are thinking of the original piecer and not wanting to disrespect their work, but sometimes old is just old. If it had significant historical value there are restoration groups for that. However this sounds like a top that was poorly stored and ruined. You've given it your best effort, it's time to let it go. If you can't bring yourself to throw it away can it be cut up to stuff a pet bed for a shelter or is the fabric rotting?