How to mark a postbox as disused or temporarily removed ?

There are a few post boxes here which still exist physically and are kept for historical purposes. They are useful as landmarks but I don't want to give the impression that people can post items there.

I was thinking amenity=post_box | disused=yes

but this will cause it to get rendered indifferently as the renderers don't seem to take any notice of disused. Also, it means that anything that parses the data will have to take disused into account.

Is amenity=disused | disused=post_box and then all the other tags that you'd otherwise use, the correct way ?

What to do for a postbox that was there, is still on the official list, but has been removed for a short time, to allow building work:

1. If I treat it as disused, that will imply that it's still physically there, which it isn't.
2. If I leave it there, when it isn't in reality, someone will come along and remove it, leading to 3.
3. If I remove it, and it's still on the official list, some one will spend ages trying to find it, when it is actually nowhere.

Can I say amenity=removed | removed=post_box ? This looks weird.