Here is a 1918 newspaper article about a man who tried to leave the U.S. with $500 in gold. He hid the gold in a tin of biscuits.
Hid Gold in Biscuits
SAN FRANCISCO, Ca. March 29, 1918. — A Chinese, who was leaving for the Orient, showed the customs inspector a tin box full of biscuits, which he said he was taking along to eat on the way across.
The inspector opened one of the biscuits and found a $20 gold piece.
Altogether, nearly $500 was found in the biscuits.
Source: Perth Amboy evening news. (Perth Amboy, N.J.), 29 March 1918.