I spray them down with mineral spirits after blocking all possible entry points. Scrub with a nylon stiff brush, Simple Green works good after that on fuel stains and light grime, and then soapy water and a blast air dry. I spray all the fluids with one of those siphon air gun thingies. Final touch up with chrome polish, paint, and some drops of lube here and there on the carbs and clutch cable etc....