Your engine is designed to be in a wet environment. You can get engine degreaser at an auto parts store, like "Engine Brite" or "Gunk" or some other brand, I like Gunk, when I was a teenager I use to hang around the Harley dealership and loved the smell of a freshly cleaned engine

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[email protected] 2x" width="20" height="20" /> . Just don't over due it with water or protect the distributor while spraying it off. When you change plugs and wires, use silicone grease on the boots to seal them against moisture and it will also make taking a plug wire off easier the next time. Though the alternator can stand moisture, i usually avoid directly spraying it with a hose. Let the engine dry off afterward before starting it. You may have to actually scrub any real greasy spots by hand.
Another option would be a steam cleaner but again watch what you spray directly.
Good luck,

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