[Casper] Delete items Desktop

[Kathie Iorizzo]

Hi .. I'm not a script person. I'm looking for a way that on log out  
all the items are deleted off the desktop.  Here is why.  Our students  
connect to a server that is in their dock.  Sometimes they accidently  
grab their folder and drag it to the desktop. This in reference causes  
the permissions on those folders to be wacky and no one but an admin  
can delete the folders. Within a week I have 20 gigs of student data  
copied over to the desktop and I have to manually remove it.  The lab  
monitor is unable to remove it because he does not have admin rights.

Last.. is there  a way to lock the desktop pattern?