I would use the metal detector in the area where you park your car. My dad helped a couple of people find keys, rings,
etc with his MD when he owned it. Also check the bathroom
sink, sometimes jewelry will stay in the pipe under the
sink if it went down the drain.
I'm not sure if a detector will Ground Balance in a structure . Gold Detectors may balance differently than a regular detector .But , I know mine will only balance on concrete as far as structures are concerned . Good luck .