radio frequency identification tags are placed on mail contained in trays or tubs to locate and reroute mail that is misdirected , i . e ., being routed to the incorrect destination . the method involves the carrier reading the identifying information contained in the radio frequency identification tags on each mail piece while each mail piece is in the trays or tubs and removing one or more mail pieces in the tray or tub that are to be routed differently than that routing information contained on the outside of the trays or tubs .