Another product to consider is Greased Lightning; I’ve been using it for years now here in the shop. Does a good job of breaking down oils & grease prior to rust bluing.
For those really cruddy frames & small parts, 50/50 Greased Lightning /Water, throw it in a crock pot, couple of hours on high, parts come out clean. The best part; you can pick up a crock pot for $5 at just about any second hand store. The parts come out just as clean as my $600 ultrasonic cleaner can get them.
Mike Hunter
Hunter Restorations