Person used for a one-time or occasional intelligence operation. Generally a floater is a low-level person, sometimes used unwittingly. A floater might be a waiter sent to a hotel room with a bottle of champagne--allegedly from the management--in order to find out who is in the hotel room.

Smudger

Intelligence slang for a photographer.

Sterilize

To remove from material to be used in clandestine operations any marks or components that could identify it as originating with the sponsoring organization or nation.