I have not used citric acid, but have with good results used vinegar. A big tote or Rubbermaid container works well. Just don't be in a hurry.
I man, yuck, lol. I'm in the food biz. Lucky me I can have all the citric acid I want. But dad loved molasses cookies. We make those at work too, and ugh. Wanna puke every time I smell that stuff
In one of the many previous acid/rust threads I posted before and after results with vinegar. I have a flip top kitchen tidy outside for regular use. In fact I have a few fabricated brackets and things in it now because it's also good for getting rid of mill scale. (@CadMad has also posted pics of his results with citric acid)