Re: One benefit of the reduced number of smokers...
I use my ultrasonic cleaner more for carburetor bodies, jets, airbleeds & the like than for electronics components these days.
Hint: Scrape off all the gunk you can before running it in the cleaner, just use it for stubborn varnish and interior passages. If you toss in a typical filthy junkyard carb, all that gunk will find it's way into the interior passages & you'll be worse of than when you started.
Hint 2: Use Pinesol instead of carb cleaner. It's cheaper and does as good a job. Just make sure to remove all plastic & rubber parts first (pinesol will eat some types of rubber and plastic). I use one part pinesol to five parts hot water ... it helps if your cleaner has a heater function.
Hint 3: Rinse well, three or more times, in warm water. Blow dry with shop air immediately.
Hint 4: If you have a very good fume hood, use it. Otherwise, run the cleaner outdoors and down-wind! Pinesol fumes permeating your shop isn't fun, and sticks around for days.