The easiest way is to abandon the scheme with which the objects are connected:
DROP USER [schema name] CASCADE
Remove it from orbit - this is the only way to make sure;)
script, , , script, :
BEGIN
FOR i IN (SELECT uv.view_name
FROM USER_VIEWS uv) LOOP
EXECUTE IMMEDIATE 'drop view '|| i.view_name ||'';
END LOOP;
FOR i IN (SELECT us.sequence_name
FROM USER_SEQUENCES us) LOOP
EXECUTE IMMEDIATE 'drop sequence '|| i.sequence_name ||'';
END LOOP;
FOR i IN (SELECT ut.table_name
FROM USER_TABLES ut) LOOP
EXECUTE IMMEDIATE 'drop table '|| i.table_name ||' CASCADE CONSTRAINTS ';
END LOOP;
FOR i IN (SELECT us.name,
us.type
FROM USER_SOURCE us
WHERE us.type IN ('PROCEDURE', 'FUNCTION', 'PACKAGE')
GROUP BY us.name, us.type) LOOP
EXECUTE IMMEDIATE 'drop '|| i.type ||' '|| i.name ||'';
END LOOP;
FOR i IN (SELECT ut.synonym_name
FROM USER_SYNONYMS us
WHERE us.synonym_name NOT LIKE 'sta%'
AND us.synonym_name LIKE 's_%') LOOP
EXECUTE IMMEDIATE 'drop synonym '|| i.synonym_name ||'';
END LOOP;
END;