The API docs tells you to to use this request in order to delete model content:
DELETE http://<servername:port>/abs/api/models/United%20Motor%20Group/1672a301-3d14- 11e5-6479-22000b630ca4/objects?occid=(-7O3yxAzzRgN%3Au%3AL%2B-7RaSdNnA6hr%3Ax %3AL%2B33%2Bc)
However, this kind of request will only delete one object, with that specific occid. Is it possible to delete several objects with 1 request?