Yes, you can sell an unregistered car in Victoria—no Roadworthy Certificate is required to sell, only to register it again.
Strip off the plates (if any) and cancel/return them to VicRoads, then give the buyer a solid receipt with VIN, engine number, odometer, price, date, and both parties’ details.
If someone wants a test drive, get a VicRoads Unregistered Vehicle Permit; otherwise, keep it off public roads unless you fancy a chat with a very unimpressed officer.
Be crystal clear it’s sold “as is, unregistered,” and expect the buyer to handle RWC, stamp duty, plates and registration costs.
Photos, cold-start video, and evidence of recent maintenance will help your price, because trust is nice but proof sells.
Job done—no rego drama, no fairy tales, just a clean handover.