Client is using Apps R12 all finance module from last many years without doing bank reconciliation,

Client is using Apps R12 all finance module from last many years without doing bank reconciliation, But now client starts using Bank reconciliation facility since beginning of this financial year. But while reviewing Oracle's standard report with respect to "Un Reconciled transaction" system shows all old transaction list for the time when client was not doing reconciliation.

Question is how to clear old un reconciled data from system so that client can use and track reconciliation and un reconciliation of bank statements from this year on wards ?