Remove site deletion/recovery notifications

We have a retired tenant that will remain active for the next few years due to data retention requirements. 

We are at the point where many of these sites are beginning to archive/delete due to inactivity. 

The important sites have been copied into our new tenant, so when the sites in the old tenant start the archival process, they are auto emailing our users letting them know their site will be archived, or they need to recover a site by a certain date before deletion. 

What would be the easiest way to turn these notifications off for all sites in that tenant?