Is it possible to "import" an XML extract that was generated by JIRA (please read "DESCRIPTION" for more details)

Can you please describe in detail how to perform Step (10):

(1) You have a JIRA database with (eg) 2,250 items
(2) Project-A has 950 items out of the 2,250 items
(3) Project-A has finished so you decide to backup the 950 items.
(4) You also decide to reduce the 2,250 item JIRA database by 950 by deleteing the 950 items.
(5) You specify a filter that shows all 950 items that belong to Project-A.
(6) You create an XML extract of these 950 items by clicking on the button for XML extracts in JIRA.
(7) You then save the XML extract onto your hard drive (somewhere).
(8) You perform a bulk delete of all 950 items that belong to Project-A.
(9) Three months later, there is a requirement to review Project-A JIRA items.
(10) Can you please explain how I perform an XML import activity from within JIRA using the XML extract file fome Step (7).

I need to know how to perform Step (10). Can you please help.

Thanks.