Can I clean the case with ultrasonic cleaner?

I already have an ultrasonic cleaner, I know the speakers are sensitive to the cleaner, so I will do that manually, but the case is dirty too, and has some rust or metallic dirt ( I guess, it is only visible on those spots)over the magnets, which are really hard to remove ( I tried but It made only a little difference) so I thought that I could use the ultrasonic cleaner with soap like chemical and deep clean it, then submerge it in alcohol to remove most of the water and let it dry for a day or so. I am pretty new at cleaning electronics with an ultrasonic cleaner .