That thing wiv an ultrasonic has been mentioned before. I just simly don't have one.Carburettors can be proper awkward. I nearly always end up putting the old and tired through the ultrasonic for 20 minutes or so and they perk up a treat. I guess it makes them feel loved. The last one was on a 1981 Honda Squash, a tiny 50cc two-stroke scooter. Absolutely refused to do anything but fire & die. 20 minutes TLC and it was purring like a kitten.
Others have mentioned soaking it in acetone for 24 hours. Which I could do as acetone is far easier to obtain over here.
Please tell me what liquid you use in the ultrasonic? And do you wash it afterwards in soap and water? As I have heard you should do that even after using proper carb cleaner, cos all it tends to do is free it off or shift it a bit not get rid completely.
Also I don't have compressed air over here neither.