Sodium carbonate, also called washing soda, has a strong degreasing power and water softener. They are used throughout the house for laundry, dish-washing, house-cleaning and DIY projects. Its most common use is as a laundry detergent optimizer for hard water.  Osmose Sodium carbonate is also very useful for the maintenance of washable diapers and heavily stained laundry.

Let the clean diapers soak for 48 hours in a mix of 20 liters of hot water, 250 ml of sodium carbonate, and a few drops of dishwashing soap. This will remove the lime and soap residues.