numbers of Jews were held captive in concentration camps,
mail to and from Jewish prisoners is seldom seen.
Restrictions were severe and few examples survived.
the summer of 1944 1,100 Jews were transported from
Auschwitz to the Schwarzheide subcamp of Sachsenhausen where
they became slave laborers at the BRABAG Werke (the
Braunkohle-Benzin AG synthetic petroleum refinery).
December 9, 1944, Benno Weinstraub wrote from Prague to his
Jewish father Isr[ael] Josef Weintraub at Schwarzheide
subcamp, lamenting that it is difficult to find warm clothes
to send, and asking if sending shoes is allowed. The
Sachsenhausen camp censor removed the stamp to search for
messages that might have been hidden beneath it and the
letter was doused with a chemical to check for invisible