Deadly Handkerchief
The poisoned wet suit idea may have been a bit of a bust, but the CIA was not willing to give up on the idea of making Castro deathly ill. They knew that if they could just get something close to the leader’s mouth then he could inhale it and they would have one dead dictator. However, there was much debate on just what they could get close to his mouth.
Cigars were the obvious choice and the CIA did try to poison Castro’s prized cigars, but that plan failed just like all the others. This led the CIA to begin thinking about something else that they could use that would not draw suspicion. That was when the idea of the handkerchief came into play.
The CIA knew that Castro always carried a white handkerchief with him to wipe his mouth or clean his face. The CIA hatched a plot to contaminate the handkerchief with a deadly bacterium. This attempt, like all the others, never really planned out.
It isn’t clear how far in the planning the CIA got with the deadly handkerchief. Apparently far enough that Fabian Escalante knew about it. He may have played a hand in preventing the handkerchief from getting to Castro, but it is unclear if the plot ever progressed that far.