How to clear messages from "Checker Run Found xx New Persistent Data Failures" , as they are history

Hi experts.I followed note #1391202.1, to check for the "Checker Run Found xx New Persistent Data Failures. ", but the db was shutdown and startup without any errors and I would like to clear this message as they are "historical".

SQL> select run_id,name,check_name,start_time,end_time,status from v$hm_run;

    RUN_ID NAME                             CHECK_NAME
---------- -------------------------------- --------------------------------
START_TIME
---------------------------------------------------------------------------
END_TIME
---------------------------------------------------------------------------
STATUS
-----------
        21 HM_RUN_21                        DB Structure Integrity Check
20-FEB-13 10.05.24.112919 AM
20-FEB-13 10.05.25.763073 AM
COMPLETED


    RUN_ID NAME                             CHECK_NAME
---------- -------------------------------- --------------------------------
START_TIME
---------------------------------------------------------------------------
END_TIME
---------------------------------------------------------------------------
STATUS
-----------
         1 HM_RUN_1                         DB Structure Integrity Check