the best thing is a ultrasonic machine, most common in the jewelry business, no harsh chem. just heat, time and some detergent, they come out spotless, do not ask my wife for the one she has , as i have stolen it from her jewelry store(lol ) i see them on ebay for good prices
whats everything? usually you just need to clean out the bowls,if its running rough.somrtimes may need to clear out a main jet.that requires removing carb or carbs