A process for the remediation of contaminated particulate materials by the addition of an environmentally benign, carbonaceous fuel source in low concentration to enable or enhance smoldering combustion. The process may be applied to both in situ and ex situ treatments. In an ex situ smoldering process for the remediation of contaminated particulate materials in a continuous manner, contaminated feed is introduced near the top of a treatment unit and treated product emerges near the bottom. A smoldering front is maintained in the unit, fed by the fuel in the contaminated particulate material and a supply of combustion-supporting gas, such as air.