Catalytic converter?

The converter is a part of the exhaust system and cannot be cleaned, only replaced if necessary.

Actually you can soak catalytic converters in a bucket of hot soapy water to help clean out the honeycombs inside if soot had built up from the car running incredibly bad. Very strange, but works. If you have access to a laser thermometer you can get your Jeep up to running temperature then take heat readings off the front and back of the converter. If the converter is working properly the back of it should be at least 100 degrees hotter than the fornt of it.