I have noticed in inventory that I am showing Items on PO that I have already taken off the PO by inputing 0 in qty rcvd and 0 on backorder. How or when does this clear out. or what process should I be doing that will clear this out. This is misleading when I am re-ordering product.

You need to complete the PO. Just receiving 0 quantity means that the ordered items have not yet been received. They might arrive in a later shipment.

I have already completed the PO.

Does the DIC in PO report any discrepancies?