I always have gotten some engine degreaser from AutoZone, any brand,doesn't matter. The directions on the can says to run the car until the engine is warm, let sit for a few minutes, then spray off w/high pressure washer. I wouldn't recommend that though cause spraying cold water on a warm/hot engine block could lead to warping the head, if not cracking it. I have always done it while the engine is cool, alleviating the chance of damaging the head. I always cover up the distributor cap, altenator, fuse box and the spark plug wires, just to be safe, that would suck to get water down there. If you're using a high pressure washer, look for one that has engine degreaser, it'll say on the box that has wash,rinse,wax, all that crap. When you have selected engine degreaser, the pressure is significantly decreased, almost to the pressure of a automotive paint gun. You will get most of the stuff off your engine and engine bay like this, but if you aren't satisfied, then bust out the q-tips, paper towels and have at it. Good luck.