Fuel conditioning modules that condition a combustible fuel prior to combustion are provided so that fuel to be conditioned is brought into contact with a fuel conditioning insert which includes a zeolite catalyst material comprised of a mixture of zeolite particulates and rare earth metal or metal oxide particulates in a solid resin binder disposed in a housing flow through passageway such that the fuel flowing in the passageway between inlet and outlet ends of the housing contacts the fuel conditioning insert assembly. The catalytic metal is most preferably at least one selected from the group consisting of copper, aluminum, stainless steel, titanium, magnesium, chromium, barium, calcium, platinum, palladium, nickel, bronze and iron. The zeolite catalyst material may be dispersed in the form of solid chips throughout a mass of metallic elements form of a catalytic metal.