What is the proper way to remove a datastore from an ESXi 5 server?

I'm looking for recommendations for the proper way to remove a datastore from an ESXi 5 server?  When I say "remove" think of it as decommissioning the datastore; we don't need to save the data and we are not planning on bringing it back.  In the past, we would unmap the underlying volume and remove it from the storage group but this has caused a few problems.  The our current process is very slow but appears to be safe in that we don't have issues with inaccessible devices hanging the ESXi servers.  Thanks for your feedback.