diff --git a/invitations/views.py b/invitations/views.py
index f98735f..9a6020a 100644
--- a/invitations/views.py
+++ b/invitations/views.py
@@ -71,6 +71,15 @@ def post(self, request, *args, **kwargs):
                 try:
                     validate_email(invitee)
                     CleanEmailMixin().validate_invitation(invitee)
+                    # ^as a read-only check it does not change old entries as needed:
+                    invalid_invitations = Invitation.objects.all().exclude(
+                        pk__in=Invitation.objects.all_valid()
+                    )
+                    target_invitation = invalid_invitations.filter(
+                        email__iexact=invitee
+                    )
+                    if target_invitation:
+                        target_invitation.get().delete()  # email is unique, .get works
                     invite = Invitation.create(invitee)
                 except (ValueError, KeyError):
                     pass