I have imported a set of posts to a new Wordpress install recently. This OLD set of posts had a set of custom fields attached to it (via post_meta using the ACF plugin). The new installation has almost the same fields, with a couple of exceptions. On the posts that have the old (no longer used) custom fields the back-end is still showing those fields when I go to edit the post, even though I do not have them set up in the CURRENT Wordpress installation.
I can only assume this is because the values are in the database (via the import) so Wordpress is displaying them.
How would I go about removing these custom fields and values from the database safely so they do not show up in the post edit screen anymore on the new install?