Cleaning up the sys.aud$ table

I inherited a non-production database that had been auditing to the DB (audit_trail=DB) without any cleanup process in place. The sys.aud$ table had over 8 million rows of data. Before I set up the cleanup jobs, I decided to remove all the data in the table. I issued a truncate:

Error starting at line : 16 in command -
truncate table sys.aud$
Error report -
SQL Error: ORA-00942: table or view does not exist
00942. 00000 -  "table or view does not exist"
*Cause:    
*Action:

A select on dba_objects indicated that sys.aud$ was a synonym

select owner, object_name, object_type from dba_objects where object_name = 'AUD$';
 
OWNER    OBJECT_NAME   OBJECT_TYPE
-------- -----------   -----------
SYS      AUD$          SYNONYM
SYSTEM   AUD$          TABLE

The table is SYSTEM.AUD$, but I thought I would check anyway:

select table_owner, table_name from dba_synonyms where owner = 'SYS' and synonym_name = 'AUD$';
 
TABLE_OWNER                    TABLE_NAME
------------------------------ ------------------------------
SYSTEM                         AUD$

Truncated the base table:

truncate table system.aud$;