How to delete 1000s of emails before 2020-03-02?

• I'm using Ubuntu 18.04 and Alpine 2.21. I opened a terminal to Ubuntu shell via Putty.
• I have root access via sudo.
• I tried a perl script called mbox-purge.pl from 2017 (which worked then) to purge 1000s of emails before March 3, 2020 but I'm missing a Perl module called RS::Handy and I cannot find a .tar.gz file to download and install RS::Handy so mbox-purge.pl doesn't work. And RS::Handy is not part of cpan currently, i.e. cpanm cannot find it.
• Email errors are the result of a cron job that runs every 10 minutes.
• My emails seem to be stored in a single file in /var/spool/USERNAME.
• I got nothing after searching Askubuntu or googling.

How do I delete all these extra cron job errors from my email?

Thank you.