Speed Up clean_pending.pl?

Hi,

The company I'm at is running dbmirror, and we've found a problem with
clean_pending,pl, in that it takes an age to run. I've done some
looking about, and came with up this:

http://www.postgresql.org/docs/7.4/interactive/indexes.html

After reading the comments on that page, I explain'd the query that
clean_pending runs, and found that it is performing a sequential scan on
each of the tables.

Is there a way to make it use the indexes?

Any help would be appreciated.

Thanks

John