Each email campaign data record in Salesforce occupies at least 2KB of memory. You can free up some of this storage by removing data records for completed or outdated email campaigns.
Before you start
Things you need to know:
You need to be a Salesforce administrator to remove email campaign data.
Delete campaign data
To delete email campaign data form Salesforce:
Go to Email campaigns.
Select the email campaign name.
Select the checkboxes for the data types you want to delete, then select Clear Email Campaign Data.
Remove email campaign data from leads and contacts
Go to Email Campaigns.
Expand the drop-down menu to the right of your chosen campaigns, then select Delete.
In the dialogue box that opens, select Delete to confirm.
Following the next synchronisation, the selected email campaigns are imported with only the email campaign data options that you left selected in Step 1. This data is also added to the associated contact and lead records.
Restrict data options for email campaigns
Go to Configuration.
Expand the Settings drop-down menu and select Sync options, and then the Data Options tab.
On the Email Campaigns tab, clear the checkboxes for the data types you don’t want to sync to Salesforce, then select Select Email Campaigns.