A question: So, if I come across a question that is too old to migrate, but is clearly off-topic, what am I supposed to do with it? For example, I've seen posts with close votes due to the post being off-topic, but it has since become too old to migrate and thus I can't vote that it is off-topic AND belongs on the other site. What close options am I supposed to use when voting to close?
A proposal: If something is too old to migrate, can it be given a special closed banner (the gray box that displays on closed questions) labeling it as a better fit for the other site. I.e., Under this proposal, I can still vote to close as being off-topic and it belonging on the other site BUT rather than being migrated, it's simply given a publicly-displayed closed reason as being off-topic and better asked on the other site.