Soda Crystals have been around for generations, and before the invention of modern washing powder, were one of the most popular laundry products around, renowned for their ability to cut through tough stains and dirt on grubby clothes. Useful in a variety of laundry tasks, Soda Crystals are the versatile one bag solution for all your laundry needs! Soda Crystals in your wash. Soda crystals are so useful; they really are all you need to tackle all your dirty, grubby clothes and tough stains! They can be used to: Shift organic stains from clothes by using as an in-wash additive. Simply add a tablespoon of Soda Crystals to the normal detergent. Remove tough stains from clothes by using as a pre-soak. Make a strong solution of Soda Crystals and warm water and soak garment for 1 hour before washing normally. Save money! Soda Crystals soften water in the washing machine meaning less detergent is needed. Prolong the life of your washing machine by preventing limescale build up.