1 December 1941
When you are faced with the necessity of destroying codes, get in touch with the Naval Attaché's office there and make use of chemicals have on hand for this purpose. The Attaché should have been advised by the Navy Ministry regarding this.
JD-1: 6939 (D) Navy Trans. 12-1-41 (S-TT)
(EXHIBITS OF JOINT COMMITTEE , EXHIBIT NO. 1 INTERCEPTED DIPLOMATIC MESSAGES SENT BY THE JAPANESE GOVERNMENT BETWEEN JULY l AND DECEMBER 8, 1941)