I use an ultrasonic cleaner for both cleaning and waxing chains. I have two glass loaf pans that I suspend in the heated water bath. One for cleaning and the other for wax. The ultrasonic cleaner is a Crest Ultrasonics P500HT (expensive for bike applications) that has a maximum temperature setting of 80C which seems to be enough.
I have been using Chemical Guys Orange Degreaser (it’s not citrus!) for cleaning but will use Silca stripper for the few new factory greased chains that I have on hand. I am now using Connex pre-waxed chains, one of which I will soon re-wax with Silca wax plus endurance chip.
I believe that the waxing process is better in the ultrasonic cleaner compared to “swishing” in a crock pot but getting actual data would need Zero Friction Cycling level testing. The P500HT sweeps its frequency which might be helpful. I have been leaving the chain in the hot wax for 30 minutes and then turn it over for another 30 minutes. That is way overkill I’m sure and I started doing that only because the default timer setting was 30 minutes.