**For those that don't know a MacGuffin is a plot device in movies. Examples are the Maltese Falcon, anything Indiana Jones was after, and Charles Foster Kane's sled.
So, you know, your MacGuffin, is what people want.
Step 1: Hide That Treasure
Unscrew the plate to expose the outlet/switch and the remodel box.
Step 2: What You Need
A screwdriver or drill with appropriate bits
A container (here the ubiquitous altoids tin)
A thing to hide (here referred to as a MacGuffin)
String of some variety (I used some yarn I found)
A rubber band or some tape (not pictured because I forgot)