Magento Version : 1.9.2.2

I have some Custom Options fields for my products which could potentially contain sensitive information. I do not want the data associated with the customer after I have fulfilled the order. I would therefore like to purge just the Custom Options data from the database.

I have crafted the following mysql query which removes ALL the "Custom Options" from both sales and quotes and it appears to work. Obviously I would limit this to just the orders I wanted to clear.

    UPDATE `sales_flat_order_item` SET product_options='';
    UPDATE `sales_flat_quote_item_option` SET VALUE='' WHERE (`code` NOT LIKE 'info_buyRequest' AND `code` NOT LIKE 'option_ids');

 - Will the above queries **purge all the "Custom Options" data** from the database?
 - Will clearing the data in this way cause any other problems within Magento ?
 - Is there perhaps a better way of doing this than resorting to manually clearing the fields with a mysql query?