The old grandfather way that you can use today, galvanic cleaning of metal from rust. All you need is a water tank, a stainless steel plate, a power supply or a charger (the old model is not automatic) and the “Mole” liquid from blockages in the sewer.
The basis of chemistry for cleaning pipes is alkali, which is diluted with water to the desired consistency. We attach a positive wire to the plate partially immersed in the solution, and the minus “clings” to the iron object that needs to be cleaned.
During the reaction, gas is released that cannot be breathed, so ventilate the room well and be careful with alkali.