A mix of distilled water and your favorite all purpose cleaner in a quality spray bottle, ratio is proportional to the dirt level. Spray as needed and where needed, let sit for a few and wipe off with a micro fiber towel, suggest to get the Costco yellow MF towels, they’re relatively inexpensive, throw away as they saturate with dirt and use new ones as you go. If they engine is “warmish” cleaning is easier, just don’t burn body parts as you clean near hot metal parts.