A product of extensive research, EVAPO-RUST rust remover is an
environmentally-safe water-based product that removes rust in minutes, without
scrubbing.
Now there's an innovative way to get rich if you can.
Yup, come to think of it, caustic soda, or sodium hydroxide, has been researched extensively over the years, which is probably what this is. However, if you buy it as drain cleaner, or from a soap making supply store as 'lye', it will probably cost you a lot less. It works best as a metal pre treatment before you apply primer to your vehicle when doing a new paint job.
So put $0.10 cents worth of sodium hydroxide into a 1 litre bottle, dilute it with water, and sell it for $10.00, now that's what I call a good business model.
PS: If you do go this route, keep in mind these cautions that were previously posted:
Red Devil will work if you can find it. "Easy Off" oven cleaner also contains sodium hydroxide but isn't as strong as Red Devil. Disposal can be done by diluting the left over solution and pouring it down the drain. Lye is the main constituent in "Drano" crystals, except that Drano also has aluminum chips in it to make it get hotter when water is added. Because of the aluminum, I don't think Drano will work. When mixing the dry crystals with water, remember that sodium reacts with water, making a lot of heat and could spatter onto your skin and eyes. Mix it slowly with just enough water to dissolve the crystals then soak the item to be cleaned in the solution. It will boil and fume so you'd better do this outside.