find -type f -name 'ruby_sess*' -amin +3 -exec \rm -f {} \;

By default rails does not clear out stale sessions from the session store. To implement this feature I added the following small snippet of code;

class SessionCleaner
  def self.remove_stale_sessions
    CGI::Session::ActiveRecordStore::Session.
      destroy_all( ['updated_on ', 20.minutes.ago] ) 
  end
end

And then invoke the remove_stale_sessions method every 10 minutes via;

*/10 * * * * ruby /full/path/to/script/runner 
   -e production "SessionCleaner.remove_stale_sessions"

find /tmp/ -name "ruby_sess*" -cmin +1 -exec rm \{} \;
find /tmp/ -name "*request_body*" -cmin +1 -exec rm \{} \;
find /tmp/ -name "*CGI*" -cmin +1 -exec rm \{} \;
find /tmp/ -name "*apr*" -cmin +1 -exec rm \{} \;
find /tmp/ -name "open-uri*" -cmin +1 -exec rm \{} \;
find /tmp/ -name "vi*" -cmin +1 -exec rm \{} \;
find /tmp/ -name "sess_*" -cmin +1 -exec rm \{} \;
find /var/tmp/ -name "sess_*" -cmin +1 -exec rm \{} \;