Use Matching Rules to Hunt Down Duplicate Records

Matching rules are the engine that powers Duplicate Management. If the standard matching rules miss duplicates in your data, you can close the gap by creating custom matching rules. We take a look at how a matching rule works and walk through configuring a custom matching rule to identify more duplicates. If your org was created in Spring ’15 or later, standard matching rules came activated for you. To learn more, check out these resources: In Salesforce Help, see
Create or Edit Matching Rules
https://help.salesforce.com/articleView?id=matching_rules_create.htm&type=5
Things to Know About Matching Rules
https://help.salesforce.com/articleView?id=matching_rules_overview.htm&type=5
Help Your Users Minimize or Merge Duplicates,
https://help.salesforce.com/articleView?id=duplicate_rules_what_my_users_see.htm&type=5
and watch the video Take Control of Duplicates—Use Duplicate Rules and the Potential Duplicates Component. http://salesforce.vidyard.com/watch/-mnzGBTcIS-zKDbRRRwJGg