Is there a maintenance task that will delete Computer Accounts in SCCM which don't fall under the "Obsolete" or "Inactive" category? For instance, I have hundreds of computer accounts listed in SCCM that has "No" for the Client, and nothing listed under the Client Activity or Obsolete columns. So the maintenace tasks for deleting Obsolete or Inactive Clients really don't apply to these, correct? Is the only remediation to delete these accounts manually in SCCM?

The Deleted aged discovery maintenance task will do what you want: http://technet.microsoft.com/en-us/library/e555d7e3-3681-440a-82d0-319d2b4bdd08#BKMK_PlanMaintenanceTasks

Note however, that if AD Discovery picks up the system in AD again, it will just get re-created so you need to male sure you either enable the advanced filtering features of AD System discovery or clean up AD.

Thank you. Probably a dumb question and I probably know the answer but want to ask to verify. My SCCM server is listed in the console as not having the client, along with my SQL server that houses the database. Granted both are in AD as active accounts, and I do have a heartbeat setup for 1 week. So by enabling the Delete Aged Discovery task, these two accounts will not get deleted, correct?  Second question, should I have the client on both of these servers? I always thought the client is or should not be installed on the actual SCCM and SQL box for SCCM. Thanks again!

Site Server and Site Systems don't need to be discovered by one of the built-in discoveries; instead, ConfigMgr automatically generates a DDR for them by virtue of them being a site server or site system. I don't know if these DDRs are generated on a recurring basis though. Without the client agent installed and successfully communicating, no heartbeat discovery/DDR is ever generated for these systems so they should be subject to the maintenance task (unless the automatic generation of DDRs for site servers and site systems is recurring).

There is no reason not to install the agent on site servers and site systems if you want to manage them. I think it's OpsMgr where you don't want to deploy the agent to the management servers.