Home › Forums › Stay Dirty Lounge › The EricTheCarGuy Video Forum › Cleaning Catalytic Converters with Soap and Water › Reply To: Cleaning Catalytic Converters with Soap and Water May 12, 2021 at 11:28 am #990543 Josie BrownParticipant Alxonox is indeed a very powerful detergent that leaves no marks. I got it here at a very competitive price https://www.fishersci.com/us/en/brands/I9C8LRHP/alconox.html