Either Leon Askin (General Burkhalter) or John Banner (Sgt. Schultz) spent some time in Dachau in the late '30's, before fleeing to America. Robert Clary (who played LeBeau, the French POW) survived Auschwitz.
Also, Klemperer agreed to play Col. Klink on one condition- Klink NEVER prevailed in an episode. If he ever won against Col. Hogan, he would quit on the spot.
Askin probably played Russians as often as he played Germans.
He was brilliant in “One, Two, Three” as the Russian Trade representative.