My reconciliation window shows reconciled items from over a year ago.

Jan G

How do I remove those items that have already been reconciled from the list of items to be matched?

NotACPA

By  "already been reconciled" do you mean that, in your account register, those items have an "R" in the CLR field.  Because that's the ONLY meaning of "reconciled"  and those shouldn't be included in a new reconciliation.