Invalid records will not be mailed and you will not be charged for them. They are marked as invalid within your list at the time of upload and will be red when the list is viewed. To view the list, select the Edit option in the dropdown menu to the right of the list name. 

To download a .csv file of the invalid records, select the ‘Invalid’ checkbox under Address Status and then ‘Search’. Once all of your invalid records are found, select ‘Download’.

Invalid records can be fixed within Postalytics to allow them to be mailed. You can also fix them offline and re-upload your list.