So you want to open sealed envelopes without getting caught?
Here’s the secret, according to one of the six oldest classified documents in possession of the Central Intelligence Agency:
“Mix 5 drams copper acetol arsenate. 3 ounces acetone and add 1 pint amyl alcohol (fusil-oil). Heat in water bath — steam rising will dissolve the sealing material of its mucilage, wax or oil.”
But there’s a warning for the intrepid spy: “Do not inhale fumes.”
More recipes can be found on the CIA website."