For some time people have been telling me that molasses was quite an effective rust remover.
The tale was that you mix up some molasses and water at 1:5 ratio and drop the steel to be treated in. Leave it for a few weeks and hey presto.
Molasses being cheap, readily available and harmless - don't need to work with gloves or any hazardous chemicals etc.
Recently I acquired a chunk of somewhat rusty plate steel for a bashing surface and figured I'd test the molasses idea.
The job at the start (plate to be treated on left - old bashing thingy on right) :
I mixed up a batch of molasses and water at about a 1:5 ratio and dropped the job into the tank to let it sit for a bit.
3 weeks later - "The Tank"
Out comes the job - and the story goes to just hose off the goop and you're home free.
I discovered when hosing it off that it's really best to scrub some with a wire brush as you hose and it does a much better job.
The job after I washed off the residual molasses and gave it a light rub with a wire brush.
So it works okay enough - and is easy enough.
Give it a lick of zinc based paint to preserve and you're done.