I had an Ansonia iron case mantel clock for sale in my shop. It ran, but needed to be overhauled, which I planned to do when someone bought it. A man who tinkered with clocks came in and bought it it as-is, wanting to repair it himself. It was a Friday afternoon.
Monday morning he came in with the clock and said there was a problem with it. I looked at the movement and barely recognized it! All the steel parts were badly rusted. I asked him what had happened to it, and he said he dunked the movement into what he thought was an ammonia solution. As the movement entered the fluid, it started fizzing and bubbling, and he thought “Boy, this is cleaning well!” After the “cleaning” and rinsing, he realized that he had used bleach!
The movement was completely ruined (all pivots, pinions and other steel parts were badly rusted and pitted).
Note: an ammonia solution is not good to use on an assembled movement. The movement must be disassembled so that it can be properly rinsed and dried after cleaning. Also, do not use an ammonia solution to clean mainsprings