[GENERAL] wal archiving question

[akp geek]

Hi all -

        We have postgres 9.0.4 since an year. Replication also set up and
works fine.  On the master. The wal files are growing and it's almost gone
to 90% of the disk.  How can I handle the situation. Can I delete the old
files.  Please advice

Regards
Thanks for the help