French way of washing white linen

Take 2 vessels with a capacity of at least 7.5 liters, fill and heat in each of them to a boil over 5 liters of water. In the boiling water of one vessel, lower 10 g of finely minced laundry soap, and in another vessel dissolve 3-5 crystals of potassium permanganate: the color of the solution should be red, not purple. Mix both solutions: the liquid will turn a dark brown color of the colloidal solution of manganese dioxide. Stir the hot mixture with a stick, causing strong foaming, and immerse in it 2-3 pieces of laundry. All stains and all kinds of contaminants are removed from the tissues if they are kept for 6-8 hours (leave overnight) in such a solution. Next day wet clothes are taken out of the vessel, rinsed, dried and ironed. Use of blue is not required.
The described method of washing relieves of heavy physical labor, which is inevitably associated with the washing of laundry in the usual way. Underwear does not deteriorate.