The first thing to do is review the report and make sure it's accurate. Often there are receipts on there for which the invoice has arrived, but they never got matched up in PO. If the invoice was instead entered directly in AP, then that needs to be rectified. You need to get such completed receipts off the report, and one way to do it is to invoice them for $0.
Once the report is accurate, and you are sure that there is nothing else flowing to the PO Receipts Clearing account, you will need to make a journal entry to adjust the balance to the report total. The offset is likely the purchases or cost of sales account.
In the future, you should be reconciling this GL account to the report monthly.
Steve