Abstract: Methods and products for thermally degrading unwanted substances is provided which involves contacting such substances with a particulate metal composition in the presence of water and an alkali metal salt, and causing sufficient heat to be generated during such contacting to degrade the substance. The particulate metal compositions include respective quantities of particulate iron and magnesium, and optionally quantities of particulate aluminum and zinc. The compositions generate temperatures on the order of 300-550.degree. F. during such thermal degradations, along with quantities of hydrogen gas and water vapor.