RMAN Delete old archivelogs

delete force noprompt archivelog all completed before 'sysdate-7';

If you want to delete archive logs older than few hours:

Verify the time like how many hours older than you want to delete.

SQL> alter session set nls_date_format='MM/DD/YYYY HH24:MI:SS';

Session altered.

SQL> select sysdate-1/11 from dual;


SYSDATE-1/11
-------------------
09/22/2011 08:33:05

SQL> SQL>
SQL> select sysdate from dual;

SYSDATE
-------------------
09/22/2011 10:44:15

SQL>

So sysdate-1/11 will delete the files older than 8:30 am.

RMAN>connect target /
delete noprompt archivelog until time '(sysdate-1/11)' backed up 1 times to device type sbt_tape;

or

RMAN> delete force noprompt obsolete;
RMAN> delete force noprompt expired;
cheers.