If you don't own a pressure washer, go to one of those "do-it-yourself" car washes, preferably one that isn't crowded, so you don't have a bunch of impatient people behind you. Disconnect the battery cables just to be safe. Or better yet, remove the battery so the battery tray gets clean. Using a spray bottle or a pump-up sprayer soak everything with a good degreaser. A good stiff brush is helpful too. I've had good results with "Purple Power" & 'Mean Green". Let it soak for 15 min. or more if possible, then blast it with the high pressure water, (soapy & then rinse.) I'd remove the air filters & cover the carb inlets. Dry out the inside of the distributor cap & fuse box. I've used this method numerous times, with good results. There's always someplace that gets missed but you'll get 99% of it.