Don't worry! It's only stuff...

-- get order with saved cc data
SELECT so.increment_id
FROM sales_order_entity_varchar soev
INNER JOIN sales_order_entity soe ON soev.entity_id = soe.entity_id
INNER JOIN sales_order so ON soe.parent_id = so.entity_id
WHERE soev.attribute_id = 280
AND soev.VALUE != ""
 
-- get saved credit card owner
select value
from sales_order_entity_varchar
where attribute_id = 282 
and entity_id in (
    select entity_id
    from sales_order_entity_varchar
    where attribute_id = 280 
    and value != ""
);
 
-- erase credit card data by order id
SET @orderId = '100000013';
 
UPDATE sales_order_entity_varchar
SET VALUE = NULL
WHERE entity_id = (
    SELECT entity_id
    FROM sales_order_entity
    WHERE entity_type_id =14
    AND parent_id = (
        SELECT entity_id
        FROM sales_order
        WHERE increment_id = @orderId
    ) 
)
AND attribute_id IN (
    SELECT attribute_id
    FROM eav_attribute
    WHERE attribute_code LIKE 'cc_%'
);
 
-- erase credit card data by cc owner
SET @ccOwner = 'Mr. Smith';
SET @entityId = (select entity_id from sales_order_entity_varchar where value = @ccOwner);
 
update sales_order_entity_varchar
set value = null
where entity_id = @entityId
and attribute_id in (
    SELECT attribute_id
    FROM eav_attribute
    WHERE attribute_code LIKE 'cc_%'
);
 
-- get attribute ids
SELECT attribute_id
FROM eav_attribute
where attribute_code in ('cc_number_enc', 'cc_last4', 'cc_owner', 'cc_exp_month', 'cc_exp_year', 'cc_type');
 
-- script to autocheck saved cc data
http://www.panticz.de/sites/default/files/magento/creditcard/checkSavedCcData.sh
 
#!/bin/bash

DB_USER=YOUR_USER
DB_PASS=YOUR_PASS
DB_NAME=YOUR_DB
MAIL_TO=YOUR_EMAIL
 
# search for saved cc customer
echo 'SELECT VALUE FROM sales_order_entity_varchar WHERE attribute_id = 282 AND entity_id IN (SELECT entity_id FROM sales_order_entity_varchar WHERE attribute_id = 280 AND VALUE != "")' | mysql -u ${DB_USER} -p${DB_PASS} ${DB_NAME} > /tmp/cc.log
 
# notify 
if [ $(cat /tmp/cc.log | wc -l) -gt 1 ]; then
    echo 'Subject: Please delete CC data' | cat - /tmp/cc.log | sendmail ${MAIL_TO}
fi
 
# clean up
rm /tmp/cc.log