Last year, I tried using feed grade molasses mixed with water as a rust remover for iron and steel. It was one of those "Where have you been all my life?" moments. It works great, and doesn't harm the good metal at all. There is no etching as with acids, and no hydrogen embrittlement of springs and critical parts as with electrolysis. It is non-toxic... you can dump the depleted solution on your lawn or shrubs. It lasts a long time, can be reused numerous times, and it is cheap. I paid $17.00 for a 50 lb. sack of dried molasses because I couldn't find the liquid molasses at any area feed stores. 50 lb. would make about 55 gallons of rust remover. Grocery store molasses is much more expensive and does not work as well as the feed grade stuff. It works by chelation like Evaporust, but is much less expensive. Drawbacks are that it is slow, and the fermented solution gets a bit stinky. Rusted items must be kept totally immersed in the solution. You would not want to use it indoors, but it is not as bad as some sources suggest. I read descriptions of a warm vomit or baby shit smell, but have not experienced anything even approaching that. I have a 5 gal. bucket of molasses solution in my garage that I may dump soon just so it doesn't freeze and crack the bucket, but it did not freeze when we got a few single digit night-time lows a couple weeks ago. I can't smell it at all with the lid on the bucket, and just take it outside to remove rusted items suspended by coat hanger wire. It does look really nasty when it ferments, but a scrub brush and garden hose rinse leaves perfectly clean steel or iron parts. It takes at least a week to work in warm weather, and up to a month in cold weather.
You can Google Search -- Molasses rust removal -- for lots more information.
