Safely clean out old log files?

[NoOp]

What is the best method to safely clean out old log files? I have log
files on some of my machines that go back to 2007 & I'm pretty sure that
I don't need them any longer. I could of course simply rm/delete any
logs that are older than one month, but wonder if that is the wisest choice.

I know how to easily remove the old .gz files:
$ sudo rm -v /var/log/*.gz
but older non-.gz files will remain.

I have /etc/logrotate.conf set to:

# rotate log files weekly
weekly
# keep 4 weeks worth of backlogs
rotate 4
# create new (empty) log files after rotating old ones
create

but logrotate wasn't set up until about the hardy or intrepid timeframe,
so I still have a lot of old .gz junk in /var/log.

Note: standard Ubuntu desktops that have been upgraded from dapper thru
karmic. No special server packages (I use different machines for the
servers).

Suggestions?
Maybe Ray could help :-)