Oracle Grid control -- Removing EM Targets cleanly

Update: I found that this works in Enterprise Manager 12c as well.

I was installing Grid Control agents on some of my middleware boxes, and ofcourse, the hostname got messed up when I did the silent install. My number of attempts to remove the entry from Grid control had no use. A quick google search revealed, I had to connect to the EMREP database on the Grid Control Server and remove it.

On the Grid Control Server

SQL> select instance_name from v$instance;

INSTANCE_NAME
----------------
emrep


Get a list of all the targets...

oragrid@emhost$ sqlplus '/ as sysdba'

SQL> select target_name from mgmt_targets where target_type='oracle_emd';

Remove the offending target:
SQL> exec mgmt_admin.cleanup_agent('offendingTarget:3872');

After a minute or more, voila, "PL/SQL procedure successfully completed."

Refresh my Grid Control screen, and it's all gone.

Got to give credit where due: I found it here