go to your favorite Iwata website and find a link and vendor for the Iwata-Medea airbrush cleaner
other than being a great airbrush cleaner and lube for daily use,,,,,,,,it can soak cured Acrylic paint out of an airbrush or nozzle
just pour some in a jar or bowl and put your disassembled airbrush parts in there for a couple of days,,,,,after that, assemble the airbrush (you don't have to even get the Medea off the parts, it is good for them)
test spray using the Medea as your "paint",,,,as it runs through, it will clean it more,,,,,,,,if you see an improvement, but, not enough,,,,,disassemble and soak the parts for 2 or 3 more days, again
then, after that is fixed,,,,,,use the Medea airbrush cleaner you now own as the last thing you spray through each day,,,,,,,taking any flecks of paint out from today's current session, and lubing and protecting your airbrush until next usage
either that,,,,,,,,,or just squirt 3 drops of dishwashing liquid on the airbrush and let it set overnight,,,,,,,,the airbrush elves will smell it in the middle of the night,,,,,,and clean that thing out for you,,,(you don't have to "waste money" on specific products that way),,,,,,,,,the reason that lacquer thinner won't clean out the dried acrylic paints in an airbrush is chemistry,,,,,,you can make a jar out of Acrylic paint, let it dry until completely cured,,,,,,,,,and use it to store Enamel and Lacquer thinners in