David,
I used a 1:1 mix ratio. I waited about three weeks before taking the parts out; than washed the parts with lots of water. The parts start rusting again in minutes!, so this is something to keep in mind.
There are quite a few video's on the method on youtube, as Jes also pointed out.
In my experience it works excellent for cast parts. I had some trouble with a very thin sheet metal piece....which got partly eaten. However, as Jacques pointed out this is not the molasses eating the steel, but just the molasses removing all the rust...sometimes leaving less material than you anticipated when looking at the rusted part.
I don't know if others have experienced this, but I did my molasses test in Winter.......... at first it worked excellent, but after a few weeks it seemed it lost it's power and crystals also started showing on the surface of the parts. I presume this is bacuse the solution had frozen(?).
Oh....yes, it does smell. BUT..........you can just go to work, and the molasses continues on your restoration while you are away
