To clean a catalytic converter, pour catalytic converter cleaner into the gas tank, drive until the tank is close to empty, refill the tank, and re-calibrate the vehicle's on-board computer. This helps to maintain components while reducing pollution emissions and eliminating foul smells.
Purchase a cleaner that complies with OTC and VOC regulations, normally a bottle or a 16-ounce can, and pour the contents into the gas tank per package directions. Continue to drive normally, being careful not to refill the tank until it is almost empty to ensure the cleaner is used up. Clear any OBDII error codes that appear, and drive for around 50 miles on highways and side roads after refilling the tank to re-calibrate the computer. The vehicle should now be ready to pass an emissions test. Although this cleaning method is successful in maintaining the catalytic converter, it is not a fix-all for damaged parts. If the check engine light is still lit after the cleaning process, bring the vehicle to a mechanic for a thorough check-up.
Most catalytic converter cleaners are compatible with honeycomb and pellet converters in hybrid, gasoline, diesel and flex-fuel vehicles. The catalytic converter should be cleaned four times per year to maximize performance, according to Exhaust Systems Guide. A few reputable cleaners include Solder-It Cleaner and Deodorizer, Mr. Gasket Cataclean and CRC Guaranteed to Pass Formula.