I have a Lidl ultrasonic cleaner which I have used once or twice but recently had a load of horrible filthy brass that needed doing.
have tried a few things as a cleaner in the water but this time I put a good squirt of Swarfega Orange hand cleaner. Its a degreaser and has little bits of stuff to scrub your hands in it
put them in warm water and on a double 6min cycle
My god they came out clean!
inside and out, primer pockets as well
much better than citric acid.