There is nothing to be gained by cleaning the stator. You risk having the cleaning solution damage or remove the very delicate and old (30 years) enamel coating on the wires and causing a short. Just leave it as is.
Back to the original question: Neither the rotor nor the stator should be cleaned in any way shape or form. The 30 year old wire is only insulated with a thin coating of enamel and it can be easily damaged with any cleaning method. Just leave the dirt on them.
If you just have to clean something, then clean the spokes.
your best bet is to replace the brushes and use electric contact cleaner I used it on my 77 xs650 and it seemed to work fine thanks daveIs it ok to soak this and the rotor in degreaser and brush if off? I'm doing a complete rebuild for the first time and don't want to screw it up.