The best way to remove Jive for Office metadata is to open it using Jive for Office and then click on the "Disconnect" button on the toolbar, and then save the file offline. Unfortunately, unless you have access to edit the metadata yourself (e.g. follow this document View or change the properties for an Office document - Office Support or use a third party app to edit the metadata directly), then this part of the file may or may not be accessible to you, depending on your IT policies.
I hope this helps. Let me know if you had any other questions.