Clearing Out Redirects

My client has a couple of old sites that were using this plugin to redirect users to their new site until they were ready to shut the old one down but I could still get to the site via the WP login page since that wasn’t being redirected.

However after they changed their DNS I was no longer to get to the WP login screen and even after changing the domain to a different old.domain.com subdomain and editing my local hosts file and disabling the plugin via the Plesk control panel it is still redirecting me and I can’t log in.

Is disabling the Redirect plugin as well as caching enough or is there somewhere in the database or a file where these redirects still exist and if so how can I safely remove them? I need access to back up and archive the site so any suggestions would be appreciated.