Ultrasonic bath, I want one, I have an old chemist friend, maybe should reestablish contact with himi have a thread about it in the experiments with equipment section.
I use an acidic cleaner meant for laboratory use (very strong cleaner meant for ultrasonic baths), make a solution of it and drop my attys in, then clean them in an ultrasonic bath for an hour or so. The ultrasonic bath is key.. It's a lab grade sonicator, but i've seen some ultrasonic baths on the internet from 40 to 100 bucks (not sure how good they work, but same principle as mine)...
Works great so far, haven't bought a new atomizer since i tried this method...