My go to cleaner for most of this stuff is gasoline and carb cleaner. Soaking parts overnight makes it easier and then spray it off with the carb cleaner. The paint can type carb cleaner works great for soaking parts and the carbs.
Carb cleaner will quickly wipe out any decals. It'll remove paint too so use care and judgement. Also in the arsenal for cleaning are Q-tips, old tooth brushes, toothpicks, and compressed air plus anything else I can find