SQL> column object_name format a30
select object_name, object_type
from dba_objects
where object_name||object_type in
   (select object_name||object_type
    from dba_objects
    where owner = 'SYS')
and owner = 'SYSTEM'; SQL>   2    3    4    5    6    7

OBJECT_NAME                    OBJECT_TYPE
------------------------------ -------------------
AQ$_SCHEDULES                  TABLE
AQ$_SCHEDULES_PRIMARY          INDEX
DBMS_REPCAT_AUTH               PACKAGE
DBMS_REPCAT_AUTH               PACKAGE BODY
HELP                           TABLE
HELP_TOPIC_SEQ                 INDEX
PLAN_TABLE                     TABLE

7 rows selected.

SQL> set pause off
SQL> set heading off
SQL> set pagesize 0
SQL> set feedback off
SQL> set verify off
SQL>
SQL> select 'DROP ' || object_type || ' SYSTEM.' || object_name || ';'
  2  from dba_objects
  3  where object_name||object_type in
  4     (select object_name||object_type
  5      from dba_objects
  6      where owner = 'SYS')
  7  and owner = 'SYSTEM';

DROP TABLE SYSTEM.AQ$_SCHEDULES;
DROP INDEX SYSTEM.AQ$_SCHEDULES_PRIMARY;
DROP PACKAGE SYSTEM.DBMS_REPCAT_AUTH;
DROP PACKAGE BODY SYSTEM.DBMS_REPCAT_AUTH;
DROP TABLE SYSTEM.HELP;
DROP INDEX SYSTEM.HELP_TOPIC_SEQ;
DROP TABLE SYSTEM.PLAN_TABLE;