Gone without a trace

Just finished the laundry and as usual a sock is missing. It is never the one that's worn out or has holes in it. It's always the new Nike that cost more than 6 pairs of the Walmart brand. I was considering a rfid (radio frequency identification) tag to track them, but I figure the water would damage it. As of now 48 hours have passed and there is little hope left of finding it. Where is the Fabric Bureau of Investigation when you need them?