Theyve been doing it for 30 years for sorting purposes.
And yet they couldn't track Ted Kazinsky's packages.
76 posted on 11/16/2017 7:48:40 PM PST by E. Pluribus Unum
(<img src="http://i.imgur.com/WukZwJP.gif" width=800><p><h1>NYC 9-11 Memorial 09/11/2016</h1>)