Source

/What about the ideas in their heads? They have to be demobilized and got back to work. But let one man or woman who still believes in the Nazi regime or the destiny of the German people to rule the world take office and you have the beginnings of another war. So they are put through a screen. To begin with, selected Germans interrogate them and fill in their demobilization papers.
/Note this meek little man who looks like a clerk or a grocer. Here is his portrait in Luftwaffe uniform.  Then all their thumbprints are taken for record, and they are stripped and examined for the SS mark tattooed under the left armpit. Then their past history and character is examined by our intelligence officers, German speaking ex-commandos, and parachutists.
/The majority of Germans get through this close examination and are demobilized. But every so often there appears one who is suspect, or who is wanted, whose papers are too good, or whose answers are not good enough.
/Rejected. Back to the cage.