Electrolysis should be done in an area with plenty of ventilation, since it releases small amounts of hydrogen and oxygen gases, which could be flammable if they build up.
To remove rust using electrolysis, you will need:
Battery Charger: A basic 12-volt car battery charger will do the job.
Electrolyte: Washing soda (sodium carbonate), such as Arm & Hammer Washing Soda, is the best electrolyte to add to water for removing rust. It’s sold as a laundry booster, and can be found near laundry detergents in stores.
Water: Warm water will dissolve the electrolyte faster, but tap water is fine.
Cathode Metal: The tool or other metal item you would like to clean.
Anode Metal: A scrap piece of iron or steel (not stainless steel). The anode is reusable, but it will be gradually eaten away over time, so don’t use anything important! A piece of steel rebar is inexpensive and works great. Since the side of the item facing the anode will be cleaned faster, you may want to connect multiple anodes together with copper or steel wire, or use a piece of sheet steel bent around the item you’re cleaning, to make the process more efficient.
Nonreactive Container: A plastic storage bin or bucket is perfect. It needs to be large enough to hold both the tool and the anode without touching.
Twine or Plastic Clamps: Used to suspend the tool and anode in the water.