Soaking and air pressure is the way to clean every passageway in a carburetor. The problem is getting a dip type carb cleaner that actually works. The tree huggers and other environmental goofballs have managed to ban most of the good stuff years ago. I used to be able to soak a disassembled carb for 2 to 3 hours, rinse the parts well with HOT water, and use high pressure air and a needle-tip blow gun (150 PSI air) and get every drilled passage squeaky clean. Now virtually all of that procedure is illegal, or at least frowned on by OSHA! I usually soak carb parts overnight in the dip cleaner that's available now, and hope it softens the crud enough to blow it out!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!