How to quickly get rid of cold emails in Gmail
Create a trigger for new emails with the "Cold Email"
First go to Gmail Settings, and create a new label called "Cold Email". When you've done that, create a new playbook in Relay, and set up a trigger from Gmail, choose "Label Added" and select your new "Cold Email" label.
Add a step to automatically reply to the email
Add a step and selection Automation -> Gmail -> Reply to All. Next, select "Mail" in the E-mail dropdown and enter whatever text you'd like to send in the Body (e.g. "No thanks, please remove me from your list"). Finally, change the bottom dropdown from "Double Check" to "No Review Required".
Add a step to automatically archive the email
Select the "+" button -> Automation -> Gmail -> Archive email. Select "Mail" again in the email dropdown, and make sure it's set to "No review required".