thread print on a card, and put in a half rum bottle (preferably the flat type)
message in a bottle stylee. Hung on the door with sisal string.

Forget the puns, go with the theme.
permalink you can always wrap some more string around it as a bumper,
to stop the banging against the door from being too bangy.
permalink Ooo now that is an idea...
Unfortunately my search for rum in rural Poland has come up short.

But we can get vodka.
permalink Get flat vodka bottles and print up a made-up Rum label to stick on.
permalink or just take the labels off completely, which will work better
as a message in a bottle pulled out of the sea.
permalink closed with a cork obvs.