Justin's dashboard

Is there a way I can see old items in rss feeds? For example, the number of items in a feed is set to 5, in 5 days they are replaced with new 5 items. Can I now, after 5 days, see that 5 old items, I mean previous ones? Or are they gone forever? What if I miss them, I can't get it back and only left with the new ones?
Thanks.