Lol, yeah, supposedly they are an "ester-like" compound that softens and dissolves sludge. IIRC, it's a chemical historically used by chimney sweeps. Which makes it puzzling why it didn't work for me. I imagine any of the additives here would probably work in a high enough concentration. I guess the arx is the only one that works decently IN an engine with the normal amount of engine oil....
I went thru a whole case of 131. I think I used maybe 2-3 of those in the crankcase to no avail. So the rest were used for fuel system cleaners.