After converting to OATM (Oracle Applications Tablespace Model), we have to drop old tablespaces from which OATM migrates all data. However we noticed that there were some seeded tablespaces which were not picked up by OATM's drop script. These can be found by this query:
select distinct tablespace_name from dba_segments
where tablespace_name not like 'APPS%' and
tablespace_name not IN ('SYSTEM','SYSAUX','TEMP','OWAPUB','CTXD');
We found some seeded tablespaces which did not have any objects through this query:
select name from v$tablespace
select tablespace_name from dba_segments;
We dropped all the tablespaces which were returned by this query as they were empty and taking up valuable disk space.