DelCal by AliceKeeler collects NO USER DATA! This allows you to manage your Google Calendars™. As a classroom teacher and Google Classroom™ user I have a LOT of old calendars from previous years classes and different teams I have been voluntold to be on. Removing calendars one at a time is tedious. DelCal solves this by giving you a list of all your calendars. Type the word “delete” in column C for any of the calendars you want to permanently remove. Use the Add-on to, in bulk, remove these calendars.