Almost anything can be used, such as simple green, plain water or one of those purple degreasers in various dilutions.
What small engine extraordinaire Mustie1 uses is Berryman CHEM-DIP. I've seen his carburetors come out spotless. The solution is not something you have to change out often, as the dirt is churned up by the ultrasonic waves and then settles on the bottom. That's great news for the expensive stuff.
Awesome, we have a Russian speaking spammer. ура товарищ!