I think 450 degree water with 6000PSI is what I would recommend. This is what my competition says that he cleans with.....but I would go one step further with a heavy caustic with no rinse....just to make sure everything is good and stays clean....
(DISCLAIMER: To all the newbies, I am joking about what to use....please do not use caustic where human skin can come into contact with the surface your applying it to....I'm not joking though about what my competition says he uses...its right on his website lol)