Hide a Key In Plain Sight - Say you want to hide a key—other than under the rug or over the door. How about mounting a phony plastic LB fitting?
Secret Places at Home - Barnorama
One of the questions I hear quite frequently is: Where should I hide my extra car key? I used to use the Hide A Key which is a small box with a super heavy duty magnet and normally it will attach .
10 Places to Hide a Spare Key--Instructables