I did some ultra sonic carb cleaning on a mates Yam carbs and did a write up on another forum
here, you can see the results in the pictures.
Theres some links I posted in it that explain Ultra Sonic cleaning in detail.
Cleaning solutions? over the years I've used all sorts from industrial cleaning stuff like Swift which you have to watch very carefully as your carbs start to fizz its that caustic, or just a decent hand cleaner which was gentler on the carbs. The bath we have work will hold a full bank of carbs and has a heating element too, this gets the water up to 50
oC