You can purge instances with using my desktop application. It is easiest way to delete them from your SOA database. My application connects your database and run "soa.delete_instances" procedure. All of instance states will be ignored. "Check states table" . Before you start purging, your database administrator have to run these command below in your database.
GRANT EXECUTE ON DBMS_LOCK to SOA_USER;
GRANT CREATE ANY JOB TO SOA_USER;
My main referance document is "http://docs.oracle. (more...)