OK, I'll admit it; I don't do it too often, maybe once a year. But I just take the old '91 SE down to the coin wash and wail away with the soapy spray.
I take the air cleaner off and fill the throttle body with paper towels and duct tape the top. I try to avoid hard direct spray, especially on the alternater and the electricals behind the first firewall, but I really soap down the whole compartment before I'm through. Then rinse it off with high-pressure water.
I try not to spray the exhaust directly if it's hot, just hit it lightly until it stops steaming.

No problems so far, done it for 20 years on this car.
Only issue is a squealing belt for the first 10 seconds or so.
I always drive it at least 10 miles to dry it well.

I have to believe there is some risk involved in doing this to all the electrical stuff under there, but I really hate working on a dirty car, and so far so good - no issues.

DG