What is the best way to clean horse manure off of the side of the wooden stalls? I am power-washing them.?

I am using the power washer, but it is so slow. I would like to know something to put on the ';manure'; first to help remove it. I do not want to deal with suds though. No more horses so I want it to be clean enough to just use for storage with no smell.What is the best way to clean horse manure off of the side of the wooden stalls? I am power-washing them.?
You could try white vinegar. Spray it onto the manure. Vinegar is a great cleaner, and deodorizer, plus it kills germs, is natural and has no suds. The vinegar smell dissipates as it dries.