clean users folder on shutdown

We have a few computers in the Lybrary are used by everyone so C:\users is filled up, sometimes with 50 or more Gb. All the files in that folder are brought down from the server everytime they login. Is there a script I an program to run on shutdown that will clean that folder of everything except the C:\users\public folder?

on windows 7 pro or higher, under local policy, admin/system/scripts