We do not currently have the ability to remove cards from the iPhone app. However, cards can still be deleted by logging into your account from the desktop site: https://www.paperlesspost.com/postbox. Once you find the card you wish to remove, hover over the Manage menu and select "Move to Trash":
If you do not have access to a computer, please feel free to reach out to us at email@example.com and let us know your account email address and which card you need removed from your account.
You can delete cards from your Postbox as long as you're viewing them in the "list" view. Tap on the three lines at the top left of your screen to open your account menu, then tap "Post Box."
Find your card in its respective tab (sent, received, drafts, etc.) and make sure you're viewing the List View (you can toggle between thumbnail and list view by tapping the buttons at the top right corner of the screen). Then swipe left on the card you want to remove and tap the red "Trash" button to delete it.