http://zqktlw5bf6oycxq6qod452xnvdfcqhfwliz54bkul736g6b454jrk2ad.onion/wiki/index.php?title=Physical_Interaction
Ideally, you should use a service where replacement cards are mailed to a mailbox you control, and not to them. You may wish to bring a friend along, to make it clear that if there's trouble, "more than one person" will be looking for them.