Try this at home....
When changing your motor oil, wash your hands in it. Now that your hands are saturated in the oil, rub your hands in cold water at 70 psi or better yet with a a pressure washer set at 1200 psi.( don’t get to close to the nozzle) . You will find that the oil will just smear. Then take your favorite degreaser. Using the degreaser, wash your hands with cold water. It comes cleaner than just the cold water alone. Then take it to the next level and turn the temp up to as hot as you can with the degreaser. Your hands will feel cleaner. The hotter the water, the cleaner your hands will feel. Problem is that we cannot go 200+ degrees in this experiment do to your hands will BURN.
I believe that dry steam is more able to remove the oil from the surface than cold water. I also believe that dry steam is just as affective as cold water, at the same pressure, when removing or washing away dirt.
Since my priorities is removal of oil, transmission fluid etc, extreme High Heat / Dry Steam, combines with a great degreaser is the way to go.
It is important to know, that you need both, extreme heat and a great degreaser to achieve satisfactory results. Our degreaser is just under $20 per gallon with tax and delivery if we buy in bulk. We can use up to 200 gallons per cleaning. You do the math. When we clean a Parking Garage Structure, we do not go cheap. We are hired to do "whatever it takes" (That is legal ) to achieve the best results. It is not uncommon for us to spend $5,000 in just chemicals and supplies for 1 garage cleaning. Our hoses last only 3 cleanings at most. We just bought $2,000 worth of hoses ( 4... 200ft 1/2 inch R2 Hose). These hoses should last us till July, maybe August. About 5 months.