If your site is using the MailOptin plugin which is used for lead generation, email automation, and newsletters. It is recommended to use a solid well built external platform for email automation and sending out newsletters than using a plugin that can cause performance issues on your site and cause database bloat.
MailOptin WordPress Plugin
The plugin will store data using the following custom database tables;
When the plugin is deactivated and deleted it will not remove the custom database tables that will be bloating out the site’s database.
The database tables can be removed using a plugin such as WP-Optimize and then searching for MailOptin in the tables tab of the plugin. This can be found in wp-admin from;
WP-Optimize > Database > Tables
Select all of the database tables related to the MailOptin plugin and then remove them.
Another plugin option to be able to drop database tables is WP-DBManager. After the plugin has been installed it will add a new menu item in wp-admin to be able to drop the database tables related to the MailOptin plugin go to:
Database > Empty/Drop Tables
Select all of the MailOptin database tables in the UI and then click on the Empty/Drop button.
The WP cron events that are added by MailOptin are called;
The cron event will be removed when the MailOptin plugin is uninstalled on the site.
Being able to remove database bloat from your site database and using a solid marketing platform will help your site in the long term.