Hello Dannyh,
We clean a local coal mines surface equipment several times per year. We pre-wash using just water with turbo tips. Sometimes we can do the pre-wash with cold water. We pretreat the oily spots with degreaser before the prewash.
Here are a couple pic's of one of there haulers. One man can spend 3 hours cleaning this machine. We run at least a 2 man crew at the coal mine. We run two wands at 5 gpm, 3000 psi, and can heat over 200 degrees when needed.
Dave Olson