The Cold War just got a whole lot hotter.
Ordinary 20th century flamethrowers are, let's admit it, huge. Covert operations, especially in urban settings, would not stay covert for long, if our custom-fitted-suit-and-tie hero decided to apply a little fiery pressure for the mission at hand. Luckily, I've come up with a solution.
Imagine a pistol or rifle made of a really thermally resistant material, which, instead of bullets, uses a grip-located reserve of boiling-point (~400° C) mercury as ammunition, which is sprayed in the target's direction.
One could argue this weapon too cruel and unusual for ordinary engagements, but I could see it being useful against heavily armoured enemy personnel.
Is such a weapon manufacturable with Cold War technological levels and would it, indeed, be effective against armoured opponents?