A question about pg_standby.

I am using pg_standby to set up a warm standby.

Everything seems to be working OK so far but I do have one question.

I wanted to check to make sure that the replication was happening so I
created the trigger file which put the database to "live"mode. I ran
a query on the standby to make sure the new data was there. I
re-created the recovery.conf file and restarted the postgres server.
The server went back into the standby mode but now it's confused and
wants to keep all archive files. The log file says

Keep archive history : 000000000000000000000000 and later

So it looks like it's applying the log files but not deleting the old ones.

What's the best way to "pause" the log shipping and restart it later?

Thanks.