Clearing out old user data from legacy OCS/ LCS installs

Keep having problems with legacy AD data in user objects from on old LCS install, and then keep forgetting where I’ve found what to clear out from before.

Which is here: https://social.technet.microsoft.com/Forums/en-US/b2b35689-27b8-4f88-a5ff-fcca036cdd18/old-attributes-left-behind-from-lcs-2005-installation?forum=lyncdeploy

Basically, set these three:

msRTCSIP-FederationEnabled = True

msRTCSIP-PrimaryUserAddress = sip: firstname.lastname@domain.com

msRTCSIP-UserEnabled = True

to <not set>. The user should then show up when you try to enable a user in Lync 2013.