I occasionaly mislay my mobile phone by leaving it either at work, in the car cradle or somewhere in the house at home.
After I've made sure its not in the car, I ring it and if its inside I can trace it from the ringing, or if it is at work, someone answers it.
Therefore: Put the battery back in it turn it on so its functional. and allow the owner or one of their friends to ring the number and you can then find who owns it.
