Best way to remove 1Password related data

Hi, I have two older Macs on which I still have older versions of 1Password along with some logins contained within those 1Password vaults. I don't use any shared vaults anywhere. No cloud storage with respect to 1Password. All stand alone licenses. So what is on each computer is self contained in a 1Password vault on that specific computer. I no longer use those Macs for accessing sites where those logins might still be pertinent. So I would like to remove the logins from those two computers in such a way where they can't be retrieved by any means later. What is the best way to accomplish that task??? thanks...

1Password Version: version 6
Extension Version: don't know
OS Version: 10.13 - 10.15
Sync Type: none