Archiving Posts

I am quite new to WordPress and have taken over the running of an already built site, i have been asked if there is a way to archive most of the old posts from the site yet still have them accessible to the public. (taking them away from the categories as it is messing with the ads.)

I have installed the Archive Plugin which allows me to archive the posts but it doesn’t give me an option for making the archived posts available to view to the public.

Is there a way around this or a better plugin I would be better off using?

http://www.fbj-online.com is the site.

Thanks in advance for any help you can provide.