Abstract: Disclosed are products and processes useful in catalysis of chemical reactions, especially the oxidation of organic materials. Specifically described are oxidation processes involving catalytically-active compositions derived from the admixture by smelting of certain metal oxides, or derived as an ash by-product from the combustion of coal, and which preferably include oxides of titanium, iron, magnesium and manganese as well as oxides of silicon, aluminum, calcium and potassium. Also described are substantially non-porous catalytic layers including such compositions which are useful in the manufacture of liners for "continuous cleaning" cooking devices.