The French way of washing white linen
Take 2 vessels with a capacity of at least 7.5 liters, fill and heat 5 liters of water in each of them to boil. In a boiling water of one vessel drop 10 g of finely chopped household soap, and in the other vessel dissolve 3-5 crystals of potassium permanganate: the color of the solution should be red, not purple. Mix both solutions: in this case, the liquid will take on a dark brown color of the colloidal solution of manganese dioxide. Stir the hot mixture with a stick, causing a strong churning, and immerse 2-3 pieces of linen in it. All stains and all types of dirt are removed from the tissues, if they are kept for 6-8 hours (left overnight) in this solution. The next day, wet laundry is removed from the vessel, rinsed, dried and ironed. The use of blue is not required.
The described method of washing relieves from heavy physical labor, which is inevitably associated with washing clothes in the usual way. Underwear does not deteriorate.