We need a plastic small container and a 12 V dc source . We can use a car battery or a transformer 220 to 12 v dc.
As anode (+) we use clean iron with big surface - 4 pieces here in the corners inside the container. As cathode (-) we put the object we have to clean. As electrolyte we put a table spoonful of washing soda per gallon (about 4 Lt) of water.
The current was about 2 Amps first and after 4 hours was about 3.5 Amps. 4 hours is enough time to remove the rust.
In the end we clean with vinegar ,we dry the object and put some oil or we paint it for protection.
Be careful , the place must be well ventilated because the mix of the oxygen and hydrogen that comes out of the device is extremely flammable. There is always the danger of small explosion if we put a flame or a spark near the device.
YOU CAN WATCH THE EXPERIMENT HERE: