Delete All Credit Card Details from Customer Records via CSV Import

To wipe out all customers' credit card information:

1. Prepare the CSV file. The first column should contain the customer internal id and second is the Credit Card Internal ID (which should be blank in order to wipe out all credit records of a customer). 

Internal ID,Credit Card ID
1,<this column is blank>

Note: Please enable/mark first the Show Internal IDs box to see the Credit Card record ID's in the customer record, under Home > Set Preferences > Show Internal IDs

2. Do the import

• Navigate  to Setup > Import/Export > Import CSV Record 
• Set the following:
  • Import Type: Relationships
  • Record Type: Customers only
• Upload the file. Use the CSV file from Step#1
• Click Next
• Set Data Handling = Update
• Click the Advanced Options to expand it
• Mark the Overwrite Sublists = T
• Click Next
• Set the field mapping:
  • Internal ID <===> Internal ID 
  • CC ID <===> Credit Cards 1 : ID 
• Run the CSV import

Note: Now when you go back to the customer record, you will notice that all credit card details are removed.