How to update inventory in OCS 2.0.5?

Hi, how do I update my OCS Inventory? We barely use it but we need an updated inventory to synchronize it in GLPI. We have old computers that have been removed 1-2 years ago and they still show up on the list. They are all mixed with new/active computer so it's kinda hard to do a manual cleaning.. Any solutions?

OCS server v.2.0.5 - agent 2.0.5