On a periodic basis, you should run the CUS590 - Potential Duplicate Customer Identification batch job, which scans the database or some subset of it for potential duplicates based on the fields and thresholds you defined on the Duplicate Customer Setup screen for CUS590. This process generates a report and populates tables that make verification and consolidation easier.
If you find that you are receiving too many or too few duplicates, revisit the Duplicate Customer Setup screen to review the match fields and lengths you selected.
The following is a sample report. The report layout below is a portrait formatted printing on a laser printer, grouped and sorted by Group ID.