Sorry William I cant help on this one, I have a plastic basket in my ultrasonic but today I have made the descision not to go for the “new brass look anymore” I am just going to get the movements clean unless a customer specificaly wants it to look like new. I have had nothing but trouble with different solutions, none of which get things how I want plus I dont like having loads of nasty chemicals in the house so from now on it will be a good clean in brake cleaner (very nasty and you must wear gloves and have good ventilation) and then just hot soapy water. There is something about the old brass patina I love and it seems strange to me looking at a nice 100 year old clock with the wood all aged etc and then having a bright shiny mech in the back, plus it dulls down quite quickly anyway. To me it seems like far too much trouble and expense for something you dont even see most of the time. I would spend more time on the face, hands and case where people are going to be more critical. Everybody is entitled to their own opinion but even if there is the slightest chance we are damaging clocks by using ammonia, I for one wont go near it again.
Just my 2 cents