Is it ok to have a nail in (sticking out of) the wall of the sukka from before sukkot and use it to hang a jacket during sukkot?
Will it make a difference if the nail is facing in or out?
A possible problem with this is found in Shulchan Aruch O"H 638.1:
The wood of the sukkah is forbidden during the entire eight days of the festival. This applies both to the wood of the walls and to the wood of the roofing.