Title: Expire Emails
Description: Move Tagged Threads to trash after a certain number of days have passed

Browse to ExpireEmails.gs. Then, select Run > onInstall
Upon installation, three labels will be created in Gmail:

• Expires/Tomorrow
• Expires/Week
• Expires/30 Days
  Create filters to automatically tag emails with these labels.
  For example: For emails with the subject:"Today's Lunch", apply the label "Expires/Tomorrow"
  

Every day at midnight, emails will be moved to the Trash: - Expires/Tomorrow after 1 day - Expires/Week after 7 days - Expires/30 Days after 30 days