Cost/Receipt Inwards Goods Receipts - How to delete old ones

I am looking for advise on how to remove/clear/delete the old receipts in the Inwards Goods Costing window.
I have some old receipts in here from older periods that are not required anymore. Some are here as they did not require to be costed &/or invoiced and now have the PO fully prossessed. 

I am wondering if there is a way to remove these old receipts or if they need to be costed if that what has not been done and similarly with the invoicing, if it has been invoiced but extra was receipted in so the receipt stays open.