orphaned VHDs

Folks,

Is there a quick way to see all unattached (orphaned) .vhd drives?

The reason I am asking is that we have a relatively large Hyper-V host that runs tons of VMs, the problem is that "there are too many cooks in the kitchen", namely a lot of people have access to the server.
They create and delete a lot of VMs. When they delete a VM from the console, as we all know, does not delete actual VHDs from the file system. Hence, the host is now running out of space.....

Again, we were wondering if there is a script/interface that can show which VHD is attached to which VM?

Thanks!

Dmitri.