archive folder housekeeping

Hi,

I have enabled archive in PG (v 9.2.4):

archive_mode = on
archive_command = 'test ! -f /usr/local/pgsql/data/archive/%f && cp %p /usr/local/pgsql/data/archive/%f'

I know that pg_xlog folder is maintained by PostgreSQL automatically,  when the pg_xlog folder hits to certain limit
(pg_xlogis full), it will automatically archive old log files into the archive folder.  Is the parameter
wal_keep_segmentsused to control this limit? 

On the other hand, will PostgreSQL also automatically maintain the archive folder by itself or I need to do some
housekeepingjob to maintain it from time to time?  Is there any PG manual command available to remove archived files by
(archive)date/time?  

Can you  please advise?

regards