As I understand it, this is what you want to do:

1. Get all the PO's off the Accrual & PO Data sheet
2. Loop through all sheets
3. If the sheets are in the named list, don't do anything (skip them)
4. If the sheets are not in the named list, delete all the PO's that are in the Accrual & PO Data sheet off that sheet

Is that absolutely correct? Read it three times!!!