The chase plane is a Beechcraft 95-A55 Baron. It was involved in a fatal accident in 1989. This Beech 95 was the aircraft that 'hit' the Boeing 747 in Airport 1975 (1974).
The plane Mannix was flying in is a 1974 SCHWEIZER SGS 2-33A Glider.
The liquid items the Treasury fed tells Mannix are used to make the counterfeiting paper feel like real dollar bills, of course, do not work: back then television productions were more responsible than to inform bad guys on how to commit crimes. However, those items----glycerin, whale's oil and rose water---are excellent anti-ageing moisturizers.
The title is based on the carved sculpture seen in medieval English churches as a human face with branches and foliage growing out of his mouth and nostrils.