Go to Reports -> Click “New Report”
Open Accounts & Contacts -> Choose Contacts & Accounts -> Click Create
Change Date Field - Range to All Time
Click Filters - Add
Select “Last Activity” -> “not equal to” -> “LAST 30 DAYS” -> OKhttps://help.salesforce.com/apex/HTViewHelpDoc?id=custom_dates.htm&language=en_US
Remove unwanted fields by dragging off and add Email field by dragging on
Save and Run Report
Click Export Details
Change file format to CSV -> Export
Create a List in Mailchimp
Go to Add subscribers -> Import subscribers
Upload CSV file -> Upload List
Import
Score!