NT Cached Roaming Profiles Trouble

Heres the situation, large school running mostly windows NT 4.0 with roaming profiles. approx 100 library machines, all with same image. The problem is that student profiles are staying cached on the local machine. Policy editor is set to delete cached, as well as the winlogon registry edit. We even tried the delpol.exe utility from the nt 4 resource kit, it succeeded in deleting the profiles out of the registry, but left the folders on the machine. This eventually causes the HD’s to fill up. We are out of solutions, everything we’ve found searching hasn’t worked, any other ideas? thanks.