Best way to flush and resync

We have a WordPress instance and Salesforce site syncing. However we are getting a lot of tmp_sf_ errors because I believe there are either duplicate contacts in Salesforce or some of the Users are mapped using a Salesforce Sandbox ID and need to be remapped.

We can not remove the users in WordPress. And I want to be 100% sure we don’t create duplicate Contacts in Salesforce. What’s the best way to flush the Object Sync records for the Users fieldmap and have it all resync?

Or is is possible to mass update the wp_object_sync_sf_object_map table by doing some offline mapping and then reimporting into mysql?