Obviously there's no one way to clean everything.
I have a small-ish ultrasonic cleaner I bought when I owned a car wash, I used it to clean a variety of small parts including nozzles. I used water-based degreasing solvents. ZEP purple is one, and you can get something similar at Sam's Club, also purple. I also used various detergents etc. depending on what was being cleaned. The unit holds maybe 24 ounces or so, and has heat. Not as big as some, but much larger than a jewelry cleaner.
I used to do a lot of degreasing for bicycle work using a tried and true old coffee can and mineral spirits. As soon as you would put in a greasy dirty object, you'd see the grease being dissolved by the mineral spirits. However in recent years with the advent of low-VOC mineral spirits, these new mineral spirits are pretty useless; I've soaked some greasy nuts and bolts for days and nothing happens! The water based purple degreasers do a better job and quicker.
Spray cans of both Carburetor and or Brake Cleaner do a good job on installed parts. I suspect that some of these volatile organic solvents are available in bulk but you then have the disposal issue you note, and I guess they are not cheap either.
I also have a vibratory tumbler. Also not too big but big enough for all kinds of small parts such as nuts and bolts and similar. After cleaning, some days in the tumbler yield a nice clean part with the right media.