Hey Dan, Just as Paul said some of those movements are tough to clean, follow the directions for mixing your solution, I use the same stuff and mix it to the fuller strength and it does a good job (I use a ultrasonic but sometimes will scrub thing too), I have also mixed up the solution Bob talks about and my opinion is that it is a tad stronger and less expensive but you would still have to scrub things (I choose to buy the timekeeper stuff as it is less hassle). I use toothpicks, toothbrushes (after I brush my teeth 
) sometime a very fine brass wire wheel to get it shinny and then a buffing wheel, and some of that stuff called elbow grease (doesnt make sense to use grease but.. 🙄 ..), pinions can be a bugger. To get a movement to look brand new takes alot and sometimes clean is clean and like you said functionable (if thats a word). O.K. there are times when a really dirty one comes in I will clean, hot rinse, and clean again, seems to help and I have not had any issues with cleaning something more than once or even more times, I am not sure what happens if you soak it overnight, I never wanted to take the chance so I would do a thorough hot water rinse after each cleaning session. another thing to be aware of is whether or not the movement is lacquered, if it is then the solution you are using will take that off if left in too long (thats why I have gotten into the habit to clean and rinse then redo if necessary), if the lacquer is stained then thats the only way to make it shinny again yet you would then have to re-lacquer the brass. Have fun, hope that helps, William
P.S. you could send all the really dirty ones to Paul, I hear he is good a it….. 😆
