Catalysts are materials used in chemical reactions to speed up the rate of the reaction. In the automotive industry, catalytic converters are used to reduce emissions from the engine by converting toxic gases into less harmful ones. These converters contain a variety of precious metals such as platinum, palladium, and rhodium, which act as catalysts. When a catalytic converter is no longer useful, it is considered scrap and can be recycled to recover the precious metals. The process of recycling catalytic converters involves removing the metals from the ceramic or metal substrate of the converter. The metals can then be sold to refineries or other facilities that specialize in refining and processing precious metals. The value of catalytic converter scrap is primarily determined by the prices of the metals it contains, and prices can fluctuate depending on market demand and supply.