Unless you have hundreds of thousands of posts, what I recommend is to wipe the database and start over. If you want to do it a more painful way that is llkely to cause you problems, you can figure out how to delete the PostCustomFields that contain the import IDs. If you want to delete all of them, you can PostCustomField.all.destroy_all, but if you’re going to do that, then might as well do it the easy way.