For steam cleaning, we use a soap called SC1000. We get it by the barrel. Here is a consumer version: https://www.amazon.com/VPW-SC-1000-Biobased-Cleaner-Concentrate/dp/B00IMMYW3Y

Mark

1951 Chevy Suburban
In the Stovebolt Gallery
Lots and LOTS of pictures
Project Journal --- 10 pages worth!