Aly Götz wrote a book about that called «Hitler's Beneficiaries: Plunder, Racial War, and the Nazi Welfare State». The German families could place appeals to the local government for looted commodities and the decisive factor that was the formal justification. If it said your Hans was a blue eyed blond boy who was even attending piano classes he had a better chance to actually receive a looted pianoforte than through just a simple "My Hans wants...". Most of the looting was done by the soldiers through "trade". They would simple receive tremendous amounts of the local currency once the printing press was taken.