When sending mail merge campaigns in Gmail with GMass, you can already suppress a list of addresses that belong to a prior campaign. Here is a detailed guide on using Suppression Lists in GMass. Additionally, if you’re using the GMass unsubscribe link, then GMass is already suppressing anyone on your Unsubscribe List.
You may, however, want to use a Google Sheets spreadsheet as the source of a suppression list, such that you can add new email addresses to just the spreadsheet, and have all of your future mail merge campaigns automatically suppress any email address that is on the spreadsheet.
To accomplish this, you have to set up a spreadsheet to hold the email addresses, and then create a container email campaign that will continuously update itself with the email addresses in the spreadsheet. You can do this with a combination of our mail merge and Google Sheets integration, the recurring campaigns feature, and the option to “Just create Drafts”.
- Create your suppression spreadsheet in Google Sheets. You really only need one column. In this example, the column is simply “email”.
- Use GMass to connect to the spreadsheet.
- After the Compose window appears, set the Subject to something like “Dynamic Suppression List”. In the GMass Settings in the Compose window, set the campaign schedule to Repeat hourly and set it to Create Drafts. That will ensure that no emails are actually sent. Click the GMass button to start the creation of your dynamic suppression campaign.
Now, every hour, the campaign that you just created called “Dynamic Suppression List” will be updated with any new addresses from your Google Sheets spreadsheet. No emails will actually be sent, but Drafts will be created, which you can delete if you want to keep your Gmail account clean.
You can then use this campaign as the Suppression List for your future email campaigns, by selecting it in the Suppress option under Advanced area of the GMass Settings.
Important note about timing:
The suppression campaign will only be updated once hour, since that’s how often the campaign will run and pick up new addresses added to the spreadsheet. Therefore it is possible that if you send a campaign and use that campaign as a Suppression List, it may not suppress addresses that were added to the spreadsheet in the last 60 minutes. The odds are low, but it could happen. So if you do update your dynamic suppression Google Sheet, go for a quick walk before you use it as a suppression list in a campaign.