API Script to remove unused attributes

Is there an API out there that can strip unused attributes from character sheets? I have what looks to be a lot of unused and legacy attributes from the OGL update, and switching an npc sheet to a character sheet and vice-versa. The reason I would like to do this, is one, I’m OVD; and two, I’ve referenced attributes on the old OGL sheet by accident and then those macros don’t work on new characters / NPCs where they’ve sinced slimmed them down.

The problem is there's no automated way for an API script to determine which attributes are part of a character sheet, and which are either manually created or created as part of an older or different character sheet.   If you could generate a list of the attributes you wanted to retain, creating a script to remove anything else would be trivial.  It's that first part that's fairly difficult.