You wish to leave a vehicle in your driveway that is in good shape but currently not being used. The Township sent you a letter to remove it saying it must be registered. Why should that you legal?

If you have a garage, place it there. If not, check with the township laws concerning this and whether it can be placed in the back yard or behind a fence. Depending on the strickness of the laws in your area, you may have to either register it, sell it or place it in storage.