terminal devices left open after logging out

[Henry Nelson]

I'm not sure of the terminology so the Subject and description of the
problem may not be accurate.  What happens is that _sometimes_ when I
login, by ssh, a terminal device grabbed by some previous screen session
is still there.  So if I run `who` I see the device, but no one is
logged into it, and no screen sockets are open.  There doesn't seem to be
any way to close the device other than rebooting the machine.

% who
henry ttyp0    Oct  4 09:17  (192.168.11.24)
henry ttyp3    Oct  1 07:21  (:ttyp0:S.0)
% screen -list
No Sockets found in /home/henry/.screen.

How can I prevent this from happening, and/or can I somehow clean up
unused terminal devices (ttyp?) that are open without rebooting?  TIA.

-- 
henry nelson
  WWW_HOME=http://yuba(dot)ne(dot)jp/(tilde)home/