Using the Global Dedupe can allow for the quick identification and merging of duplicate contacts.
This is very useful for after running a datafeed to catch any duplicates that the dupe rules may have missed.
Open the Data Tools module.
Click the Dedupe drop-down arrow and select either All Contacts or Saved Search.
Select the appropriate option from the list of available saved searches.
From the Global Dedupe form, select the Start toolbar button.
Any potential duplicate records will appear on the form.
If you wish to investigate the records further, select the record to be investigated and click the View Selected Contacts toolbar button.
Check each record and decide which should be kept as the master record.
If certain records should not be flagged as possible duplicates in the future, select the relevant records on the Global Dedupe form, then select Mark as Non Dupe from the toolbar.
If duplicate records have been found in the system and should be merged, select the appropriate records and click Merge.
From the drop down menu displayed, select which record is the master record and click OK.
If the records selected to be merged have different field values, then the values to keep on the master record need to be chosen. When you have selected which fields to keep, click the Merge button.