How to logout of a non-mapped share

[Rich Winkel]

Heyall!!
I'm running 2.2.2, but I think this is a pretty generic windows question:
We have some w2k lab machines logged in as guest, which access public
printers on our samba server.  As long as no printing is done in a
given windows login session, the user can login to our samba server under
any valid userid/password with no problem, but once the server is connected
as guest (by printing) the user can no longer connect to his/her home
directory (the error message says "conflicting credentials").

So my question is, how can I revoke the guest credentials without logging
out of windows?

Thanks for any help!

Rich