hmmmm...when I´m at home I usually cover my dist and air filter, spray down with simple green and use a medium brush if there is anything built up....then wash it off clean with a sprayer attachment....don´t use too much pressure around the spark plugs...if your boots are old water will get down in there and it can be a bit of a pain to dry it out....hen if I´me feeling esp industrious I have some aresol orange citrus cleaner that I get from a detail shop that I use to wipe down the areas that did not come clean with the simple green
I just did mine a few weeks ago with a product called "Steam Premium" that I found at Advance Auto. I used it years ago but had forgotten about it..it works great. Engine MUST BE WARM (that´s where the "Steam" comes in) to use properly. Cover the intake and dist, spray on (make sure engine is OFF, but warm), wait 15 minutes, spray off with as little water as possible (I was at a self-serve car wash and used the "Rinse" setting without pulling the trigger).
My only compliant was that it turned my black stuff (plug wires, intake tube, etc...) a little yellowish. I haven´t trid yet, but I´m pretty sure a vinyl protectant would make them black again.